Session K20 - Poster Session.
POSTER session, Sunday afternoon, April 29
Congressional C, Renaissance Hotel

[K20.001] Astrophysics

[K20.002] Theoretical Modeling of Observed Coronal Mass Ejections

The dynamics of magnetic flux ropes near the sun are studied by solving model equations [1,2] which describe a flux-rope-geometry coronal mass ejection (CME). In this model, a CME corresponds to a flux rope with foot points that remain anchored in the photosphere and the eruption is driven by a rapid increase in poloidal flux (flux injection). Model results, computed with a minimum of free parameters, are shown to compare well with LASCO and EIT data for numerous CME events which have flux-rope-like morphological features. We conclude that flux-rope CMEs are relatively common events with specific physical characteristics, many of which are described by the model [3].

[1] Krall, J. et al., 2000, ApJ, 539, 964

[2] Chen, J. 1996, JGR, 101, 27499

[3] Krall, J. et al., 2001, ApJ, submitted

[K20.003] Distribution of Galactic Dark Matter

In this paper we examine the rotational curves of two dwarf spiral galaxies, NGC 2403 and NGC 3198. The observed rotation cannot be accounted for by luminous matter alone, therefore there must be a substantial dark component. We found the dark matter in both galaxies to be distributed according to the equation rho(r) = b*r/(r^2 + x^2). Combining this with a distribution of luminous matter rho(r)= rho(o)* e^-(a*r), we produced a rotation curve that matched the observed orbital velocities to within 4%.

[K20.004] Numerical Modeling of Gamma-ray Bursts from Heated Neutron Star Binaries

We present numerical results of 3-D relativistic hydrodynamic calculations of the plasma emitted from heated neutron stars in a binary system near its last stable orbit. It is argued that, as the system's orbit decays, the stars will heat and emit thermal neutrinos which will partially annihilate into an electron-positron pair plasma. We model the expansion of this e^+ e^- pair plasma and find that a gamma-ray burst of total energy 10^52 ergs and modest beaming is possible.

[K20.005] Th/U/Pu/Cm dating of GCR nuclei with the Extremely-heavy Cosmic-ray Composition Observer (ECCO)

The ECCO instrument is one of two instruments which make up the HNX mission. The principal goal of ECCO (the Extremely-heavy Cosmic-ray Composition Observer) is to measure the age of galactic cosmic ray nuclei using the actinides (Th, U, Pu, Cm) as clocks. As a bonus, ECCO will search with unprecedented sensitivity for long-lived elements in the superheavy sland of stability. ECCO is an enormous array (23 m^2) of BP-1 glass track-etch detectors, and is based on the successful flight heritage of the Trek detector which was deployed externally on Mir. We present a description of the instrument, estimates of expected performance, and recent calibrations which demonstrate that the actinides can be resolved with good charge resolution.

[K20.006] Discrimination Between Possible Cosmic Ray Abundance Sources:

Different scenarios of the origin of the cosmic radiation invoke different chemical abundances of the accelerated material. A determination of the abundances of the nuclei in the cosmic rays observed in the solar system can, in principle, be used to discriminate between these different scenarios. Unfortunately, the compositional changes introduced during the propagation of the nuclei through the interstellar medium introduce serious uncertainties in relating the observed composition to that at the source. It is shown here that there are a number of "signature" elemental ratios among the heaviest elements in the cosmic radiation that should allow for clear discrimination between some of the most popular current theories of the origin. These ratios appear to be robust in that they are not strongly energy dependent nor do they depend critically on the precise details of the propagation models or parameters. The proposed HNX mission will be able to determine these ratios with the required accuracy.

[K20.007] Correlation of Upper-Atmospheric 7-Be with Solar Energetic Particle Events

A surprisingly large concentration of radioactive 7-Be was observed in the upper atmosphere at altitudes above 320 km on the LDEF satellite that was recovered in January 1990. We report on follow-up experiments on Russian spacecraft at altitudes of 167 to 370 km during the period of 1996 to 1999, specifically designed to measure 7-Be concentrations in low earth orbit. Our data show a significant correlation between the 7-Be concentration and the solar energetic proton fluence at Earth, but not with the overall solar activity. During periods of low solar proton fluence, the concentration is correlated with the galactic cosmic ray fluence. This indicates that spallation of atmospheric N by both solar energetic particles and cosmic rays is the primary source of 7-Be in the ionosphere.

[K20.008] THE ENERGETIC TRANS-IRON COMPOSITION EXPERIMENT (ENTICE) ON THE HEAVY NUCLEI EXPLORER (HNX) MISSION

The ENTICE experiment is one of two instruments which make up the HNX mission. The experimental goal of ENTICE is to measure with high precision the elemental abundances of all nuclei with 10 \leq Z \leq 82. This will enable us to determine if the injection mechanism for the cosmic ray accelerator is controlled by FIP or Volatility and to study the mix of nucleosynthetic processes that contribute to the galactic cosmic ray source. The ENTICE experiment utilizes the dE/dx-C method of charge determination and consists of silicon dE/dx detectors, Cherenkov detectors with two different refractive indices, and a scintillating fiber hodoscope. The geometrical factor of the instrument is \sim 8m^2sr. We will present a description of the instrument and its expected performance based on beam tests and a balloon flight of a prototype instrument.

[K20.009] Dark Matter, Gray Matter, and Viscous "Optical Molasses", As Due To Random Motions of Paired Electrons and Positrons, Bound in "Vacuum Space"

In the Electron Positron Lattice (EPOLA) model of space [1] the mysterious 3K thermal radiation of the sky is due to random vibrations of epola particles; they also cause the zero-point motion of helium atoms, a Brownian Motion analog. The temperature (T) of our epola region is therefore 3K. T is elevated in space regions where there are more hot stars, more nuclear activity, more injected free nuclear particles and radiation. Epola regions of T>3K are observed as mysterious "dark matter", and 100K-warm regions create the mystery of "gray matter", considered to "constitute 90the mass of the universe". Epola regions hotter than 800K emit visible radiation; at 3000K they glow like lamp filaments, and at 6000K - like the sun. At sufficiently high T, the epola "melts" into a liquid of electron-positron (epo) pairs, in which the velocity of light is drastically reduced. At 6 billion K, it turns into a gaseous mixture of epo pairs and free electrons and positrons. In this "epogas", quantum radiation laws do not hold, there are no photons, just as there are no phonons in gases. Epola hot spots may be mistaken for galaxies and stars, it is therefore imperative to find how to distinguish between them. References: 1.M.Simhony, The Epola Space, 1990, 160 pp, and The Story of Matter and Space, 1999, 70 pp (available from the author). M.Simhony, Invitation to the Natural Physics of Matter, Space, and Radiation, World Scientific, 1994 (292 pp). See the website: www.word1.co.il/physics/

[K20.010] Self Creating Universe

Cosmology has deduced that our existence began 15 billion years ago but that does not constitute a true story. When compared against infinity, the true question one must as is, ‘why did creation begin now (a mere 15 billion give or take years ago) and not at some infinite point before? What could keep the one common original source static for an infinity, and then spring forth into existence?’ Also, accelerators are actually creating atmospheres much like that within quasars, black holes and stars. This destructive/creative environment is not that of original creation, it is of that which occurs in a later stage of cosmic evolution. Knowing that it is only a matter of movement or change, understanding what is moving is the key. Regardless of how much power is used to alter the character of a particle’s matter, it does not make its essence go away, nor does it make the understanding of original essence clearer. To find the true answer of what occurred, one must look back in time and think carefully over the process of elimination to find the original creation of matter, albeit different than that of the later processes. Matter and the physical laws formed themselves in an absolute infinity of blackness prior to light and no Big Bang scenario was necessary.

[K20.011] Robert Trumpler and the (Non)Transparency of Space

Newton declared that, although light could interact with matter and be affected by it, the space between the stars was perfectly transparent. William Herschel concurred, and so used his "star gauging" to put us very near the center of a small, lenticular galaxy. The misconception survived the discovery of individual dark clouds (E.E. Barnard and others) and was incorporated into Shapley's calibration of the distance scale of Cepheids and RR Lyraes. The result was a galaxy too large and, when Hubble built on Shapley's results, a universe far too small. Those who disagreed between 1850 and 1930 (Secchi, Ranford,Wolf, King, and even H.D. Curtis) were somehow less influential. Only with Trumpler's 1930 publication (Lowell Obs. Bull. 14, 154) of the relationship between angular diameter and apparent brightness of star clusters did the community accept that all of interstellar space was capable of swallowing starlight. Mineur, during WW II, was the first to incorporate this general obscuration into a cephei distance scale (and his 1 - 1.5 mag per kpc was about right), but not until 1952, at the Rome IAU, did most astronomers catch on. It is just possible that, if this had all been sorted out earlier, Steady State cosmology would never have been proposed.

[K20.012] Tests of Physics Laws

[K20.013] Pathology-Free Modification of the Lorentz-Dirac Equation

The Lorentz-Dirac equation for the force on an accelerating electron is conventionally written in covariant form F_ext^\lambda=ma^\lambda-2 \,e^2øver 3\, c^3\left(\dot a^\lambda+1øver c^2 a^2 v^\lambda\right) However, this equation has fallen into disfavor in recent years because it admits pathological solutions representing runaway behavior or preacceleration violating classical causality. For example, force-free motion can exhibit unphysical runaway solutions of the form a(t)= a(0)\exp(t/ \tau_0), where \tau_0\equiv 2e^2/3mc^3\approx 6.26\times 10^-24 sec. Note that the first two terms of the L-D equation could originate from expansion of ma^\lambda(\tau-\tau_0) in powers of \tau_0. We propose the following differential-difference equation as a compact non-pathologial alternative to the L-D equation: F^\lambda_ext(\tau)=m\, [a^\lambda \beta^\mu -a^\mu \beta^\lambda]_\tau-\tau_0\,\beta_\mu(\tau) where \beta^\lambda=v^\lambda/c. Expansion of the bracketed quantity reacquires the conventional equation, apart from higher-order terms in \tau_0. It can be demonstrated that F=0 unambiguously implies a=0. Moreover the occurrence of the retarded time variable \tau-\tau_0 precludes any solutions with preacceleration. A more detailed derivation is given in a forthcoming paper [S. M. Blinder, ``Classical electrodynamics with vacuum polarization: electron self-energy and radiation reaction," Repts. Math. Phys., in press].

[K20.014] Doppler Frequency Shift Based on the Local-Ether Model of Wave Propagation

Consider the Doppler effect between a transmitter and a receiver moving at velocities v_s and v_e, respectively. According to classical propagation, the transmitted and received frequencies due to the Doppler effect is given by f_t/f_r=1+dR/cdt, where the propagation range R=R_t\left( 1+u_e/c\right) , u_e=v_e\cdot \hatR_t, R_t is the directed separation distance from transmitter and receiver, and v_e, v_s, and R_t are all referred at the instant of wave emission [1]. The range modification v _e\cdot R_t/c (=R-R_t) is due to the Sagnac effect associated with the longitudinal movement of the receiver during wave propagation. Due to relative motion between transmitter and receiver, d R_t/dt=v _es=v_e-v_s and hence dR_t/dt=u_es=u_e-u_s. Thereby, to second order of normalized speed, the Doppler frequency shift is \[ f_t/f_r=1+u_es/c+(v_e\cdot v_es+ a_e\cdot R _t)/c^2. \] For the case of radial relative motion without acceleration, where Newtonian relative velocity v_es is parallel to \pm R_t, f_r/f_t=(1-u_e/c)/(1-u_s/c). This is just the well-known classical Doppler formula. According to the local-ether model of wave propagation [2], there emerges one fundamental difference. That is, velocities v_s and v_e are both referred specifically to a geocentric or a heliocentric frame with respect to which the gravitational potential of the Earth or the Sun is stationary, depending on the propagation being earthbound or interplanetary. However, its effect is merely of second order. \ \ \ [1] C.C. Su, Electron. Lett. 36, 1812 (2000); [2] C.C. Su, 2000 IEEE Antennas Propagat. Soc. Int. Symp. Dig., p. 1570.

[K20.015] Resonance Absorption between Moving Atoms due to Doppler Frequency Shift and Quantum Energy Variation

Consider the resonance absorption between source and absorber atoms moving at velocities v_s and v_e, respectively. According to classical propagation, the transmitted and received frequencies due to the Doppler effect is f_t/f_r=1+u_es/c+v_e\cdot v _es/c^2, where v_es=v_e-v_s, u_es=u_e-u_s, u=v\cdot \hatR_t, and unit vector \hatR _t points from source to absorber [1]. Furthermore, based on a wave equation, quantum energies and hence transition frequency f in an atom moving at velocity v decrease with speed by the mass-variation factor as f=f_0(1-v^2/c^2)^1/2, where f_0 is that in the atom at rest [2]. By considering both the Doppler frequency shift and the quantum energy variation, we have the resonance-absorption condition: \[ f_0e\sqrt1-v_e^2/c^2=f_0s\sqrt1-v_s^2/c^2\left\ 1-u_es/c-(v_e\cdot v_es-u_es^2)/c^2\right\ , \] where f_0e and f_0s are the rest frequencies in absorber and source, respectively. If the absorber is stationary (v_e=0), then f_0e=f_0s(1-v_s^2/c^2)^1/2/(1-u_s/c). This agrees with the frequency shift of light emitted from fast-moving hydrogen atoms in the Ives-Stilwell experiment. If the source is stationary (v_s=0) and v _e is parallel to \pm \hatR_t, then f_0e=f_0s(1-u_e/ c)/(1-v_e^2/c^2)^1/2. This agrees with the two-photon absorption in neon atoms moving collinearly with two counterpropagating laser beams from an identical source [3]. However, according to the local-ether model, one fundamental difference is that velocities v_s and v_e in these terrestrial experiments are referred to an ECI frame [1,2], although slight for high-speed atoms. \ \ \ [1] C.C. Su, this Bull.; [2] C.C. Su, Bull. Am. Phys. Soc. (Apr. 2000), p. 61; [3] M. Kaivola et al., Phys. Rev. Lett. 54, 255 (1985).

[K20.016] On logical errors lying in the base of special theory of relativity

The basis of the special theory of relativity has been analyzed, namely interference experiments and calculations of Michelson-Morley, contraction hypothesis and formulas for Lorentz's transformation. The results of the critical analysis are as follows. 1. The contradiction between the experimental and calculated data of Michelson-Morley is due to the fact that they relate to different reference systems. In fact, the experimental data relate to the reference system connected fixedly with the Earth and the calculated ones to the Sun. The comparison of these data with each other is the first logical error. This error results in a contraction hypothesis and Lorentz transformation formulas. 2. For the reference system connected fixedly with the Earth, experimental and calculated data of Michelson-Morley are in complete agreement. This means that the contraction hypothesis and Lorentz transformation formulas are not in agreement with Michelson-Morley's experiments. 3. The second error follows from the first one and is that coordinates and time in the Lorentz transformation formulas are variables. This error leads to the appearing of connection between space and time. The existence of this connection is in contradiction with the principle of light velocity constancy. 4. For any arbitrary reference system the principle of light velocity constancy is valid. This is explained by the fact that light is not a material point of classical mechanics. From the above it follows that the special theory of relativity is not correct.

[K20.017] Faraday's Dielectric "No Winds" Carrier of EM Fields and Radiations, Its Mathematical Formulation by Maxwell and Unfortunate Defial

Faraday's dielectric ether (1840) consisted of yet unidentified, discrete '+' and '-' charged particles, elastically bound to one another by EM forces. Bodies move in this ether through the "giving in" distances between the elastically bound ether particles that slide apart in front of the approaching body and convene behind it. These elastic vibrations of the charged ether particles result in EM waves in the ether, not in any "ether winds" that need high energies to tear ether particles off bonds. The Doppler Effect (1842) e.g., could not occur if the motion of the emitter would cause ether winds instead of adding or deducing EM waves to the emitted waves, thus changing the frequency of the received waves. Because of the false belief that motion must create ether winds, the Doppler Effect was bitterly opposed till 1868, when W.Huggins observed it in starligt. The Doppler Effect became since one of the most useful discoveries, but the false belief in ether winds remained, Faraday's dielectric ether and its Maxwell Equations were disregarded, and the Michelson-Morley 1887 verdict was that the emitter of light does not make ether winds, hence there is no ether, no material carrier of light whatsoever. This verdict made physics unable to physically explain its phenomena. References: 1.M.Simhony, The Epola Space, 1990, 160 pp, and The Story of Matter and Space, 1999, 70 pp (available from the author). M.Simhony, Invitation to the Natural Physics of Matter, Space, and Radiation, World Scientific, 1994. See the website: www.word1.co.il/physics/michelson.html

[K20.018] Theoretical Studies on The Electronic Properties of Thiophene, Oligo- and Polythiophenes and their derivatives

During the last two decade, the oligomer and polymer electronic materials have been studied intensively. In 1980 polythiophene has been synthesised by a metal catalyzed polymerization. Till now, there are many electronic material applications in thiophene and polythiophene being proposed. In this paper, we investigate thiophene, oligo- and polythiophenes by using semiempirical quantum chemistry (AM1) and density function theory (DFT/B3LYP6-31G*) calculations to generate their geometries, HOMO, LUMO and band gaps. The excitation energies of these compounds are also calculated by using the semiempirical ZINDO method. The band gap of polythiophene is 1.8 eV by ZINDO/AM1 calculations which is a agreement with experimental value (2.0eV). The substituents effect on thiophene and polythiophenes are also studied in this work. The substiuents in these compounds are methyl, hexyl, methoxy, florine and cyano groups which are located at beta position in the thiophene ring with HT and HH couplings. The electron withdrawing group of the substituents will lower HOMO energy by the quantumn chemistry calculations.

[K20.019] Asymmetric Differentiation

Asymmetric Differentiation is the name I have given to a novel method of looking for the point of no variation of a function defined by an integral (summation). The simplest example is that of the definite integral of F(x,p) from x = a to x = b where p is some parameter. Unlike the usual method of differentiation, this technique dis-continuously breaks the range of integration into two parts and considers p goes to p + Dp for x within [a,c] and p goes to p - Dp for x within [c,b] where a < c < b. What this process reveals about the underlying function depends on the context. For example, for a normalized probability distribution it produces the median. I further illustrate via a circle (compressed/expanded with a fixed area), an ellipse (stretched/tightened perimeter of fixed arc length), and a sphere (compressed/expanded surface of fixed area). The symmetry of these figures portends the result. Several conservative physical problems are solved by considering the variation of the action---a ball thrown off a building in a constant gravitational field, the simple harmonic oscillator, the spherical pendulum, a charged particle in a constant magnetic field, and the two-body problem. Finally, the financial engineering problem for which this method was invented is presented too.

[K20.020] New Test Method for Broadband Complex Permittivity Measurements of Dielectric Films at Microwave Frequencies

We have developed a new model expression for the input admittance of a thin parallel-plate capacitor terminating a coaxial transmission line that is applicable to microwave frequencies. The expression takes into consideration the wave propagation in the dielectric section and correlates the network scattering coefficient S_11 with the complex permittivity of the specimen. It was found that the wave propagation takes place along the diameter of the specimen rather than across its thickness and that the limitations of the existing lumped element methods result from the singular behavior at the half-wavelength resonance frequency. The model has been evaluated at frequencies of 100 MHz to 10 GHz using several polymer composite films 40 \mum to 100 \mum thick with the relative dielectric constant ranging from 2 to 40. The broadband permittivity measurements compared well with results obtained at discrete frequencies using a microstrip resonator method. Especially encouraging were the accurate permittivity data we obtained for the high dielectric constant films in the microwave range where the conventional lumped element approximations for thin dielectric films failed to produce meaningful results.

[K20.021] Plasma Physics

[K20.022] Parametric Instabilities of Plasma Channels

Plasma waveguides for guiding intense laser pulses have applications in particle acceleration and x-ray generation schemes. One method to create a plasma waveguide is by breaking down a gas with a laser pulse focused through an axicon [1]. Ideally, the plasma channel will allow for guided single mode propagation of short laser pulses. However, for certain experimental conditions the channel develops periodic axial modulations. According to our model the modulations are due to a nonlinear coupling of the axicon field to the confined modes of the channel. Small perturbations in the expansion rate of the channel can scatter the incident axicon field into the guided mode of the waveguide. The beating of the guided mode and the axicon field leads to modulations in the heating rate and thus in the expansion rate. A simple model of this process will be presented.

[1] C.G. Durfee III and H.M. Milchberg, Phys. Rev. Lett. 71, 2409 (1993)

[K20.023] Resonant self-trapping of Bessel beams in Plasma Channels

Abstract. Resonant coupling and enhanced absorption in the generation of plasma waveguides using high power J0 Bessel beams, and non-shockwave induced plasma waveguide generation using a high power J5 Bessel beam are experimentally investigated and theoretically simulated. With the use of a J5 beam, a preformed plasma waveguide is generated with the smallest radius (<5micron) to date.

This work is supported by the Dept. of Energy and the National Science Foundation.

[K20.024] Propagation of Intense Laser Pulses in Plasma Channels

Extended propagation of intense laser beams in plasmas has applications in areas such as laser-driven accelerators and x-ray source development. Preformed plasma channels provide a well-established means for guiding laser beams over long distances. For an intense laser pulse the ponderomotive force associated with the laser beam expels electrons radially, modifying the channel. In addition, relativistic effects modify the refractive index. We present the derivation of an envelope equation for intense laser beam propagation in a plasma channel and discuss its scaling characteristics. Simulation resutls are presented and compared with analytical predictions.

[K20.025] Density-Matrix Description of Electromagnetic Processes

A density-matrix description is employed to investigate electromagnetic interactions of quantized electronic systems in the presence of environmental relaxation (decoherence) phenomena. Applications are made to atomic radiative transitions in high-temperature plasmas, coherent radiation processes in energetic electron beams, and optical interactions in semiconductors (bulk crystals and heterostructures). Time-dependent (equation-of-motion) and time-independent (resolvent-operator) formulations are developed. Non-equilibrium (possibly coherent) electronic-state kinetics and homogeneous spectral-line shapes are self-consistently determined from the time- and frequency-domain self-energy operators.

[K20.026] Temperature Diffusion Waves in Magnetized Plasmas

Recent experiments of heat transport in temperature filaments embedded in a large magnetized plasma exhibit spontaneous fluctuations in density, magnetic field and temperature (Burke et al., Phys. Rev. Lett., 84, 1451, 2000; Phys. Plasmas, 7, 1397, 2000). The high-frequency component (~30 kHz) has been identified as drift-Alfven eigenmodes driven by the radial pressure gradient. The low-frequency component (~5-10 kHz) is predominantly an electron temperature fluctuation and could be related to fluctuations in the primary heat source region (a slowing down electron beam) that propagate as temperature diffusion waves throughout the plasma. We present the linearized theory of temperature diffusion waves and compare the predictions to experimental observations. Numerical solutions to the nonlinear diffusion equation for large amplitude waves are explored and directions for further experiments are outlined.

[K20.027] New characteristic frequencies in cold collisionless magnetized plasmas

The additional interaction of two charged particles of the collisionless magnetized plasma of the low density has been studied. The particles are modeled as ring currents. The expressions for frequency of oscillations of these rings are derived. Both the ion-electron, and ion-ion, and electron - electron oscillations have been considered. For ionospheric conditions the oscillation frequency for electron-electron system is closed to the power lines frequency (60 Hz).

[K20.028] Recent Progress in Research of Magnetic Reconnection on MRX

It is well known that conventional MHD theories often break down in the reconnection layer even when the reconnecting plasma is globally well approximated by MHD equations. Precise measurement of the profile of the reconnection layer can provide important clues to help understand the non-MHD physics mechanisms of reconnection. The detailed structure of the neutral sheet has been measured in the MRX plasmas [M. Yamada et al., Phys. Plasmas v7, 1781 (2000)]. In agreement with Harris theory [E. G. Harris, Nuovo Cimento v23, 115 (1962)], the width of the reconnection region is on the order of ion skin depth as a simple MHD formulation breaks down in this regime. By treating electrons and ions separately, the generalized Ohm’s law describes force balance of an electron flow. In the neutral sheet we expect that the fluctuation components of electric and magnetic fields can make a significant contribution to the frictional force balance and the energy dissipation rate thus affecting the reconnection speed. Recently electrostatic and electromagnetic high-frequency fluctuations have been singled out and measured in MRX. Recently the dispersion relation of the electrostatic waves have been measured and the waves have been identified as lower hybrid drift waves. Our next goal is to find a relationship of these fluctuations with the observed enhanced resistivity and ion heating. The impact of the MRX data on interpretation of the recent space data will also be presented. Work jointly supported by DoE, NASA, and NSF.

[K20.029] Observation of Compressional Alfven Modes during Neutral Beam Heating on the National Spherical Torus Experiment

Multiple coherent modes at frequencies up to the deuterium ion cyclotron frequency were observed during neutral beam injection heating of the National Spherical Torus Experiment (NSTX). The modes were seen predominantly in the frequency range of 0.4 MHz to 2.5 MHz. They have been identified as compressional Alfvén waves excited by a resonant interaction with the energetic beam ions. The mode frequency has an inverse dependence on plasma density and increases with magnetic field strength. There has been no observation of enhanced beam ion loss associated with the mode activity. Rather the presence of the modes may enhance the transfer of energy from the fast ions to the waves which are then damped on the thermal electrons. The modes are predicted to be localized near the plasma edge. Lower freqency modes (50 – 120 kHz) were also seen and have been tentatively identified as Alfvén Eigenmodes. For these modes the toroidal mode numbers have been measured as n = 2 – 4.

[K20.030] (Re)Introducing the Reversed-Field Pinch: Recent Results from the Madison Symmetric Torus

A Reversed-Field Pinch (RFP) is a toroidal laboratory plasma confined by magnetic fields generated almost entirely by currents flowing within the plasma. As the RFP plasma evolves it is constrained by the conservation of magnetic helicity \int \mathbfA \cdot B dV. The "reversed field" refers to the toroidal magnetic field, which reverses spontaneously near the plasma boundary. This reversal is brought about and sustained by current arising from the RFP dynamo, which is generated by coupled fluctuations in the magnetic field and plasma flow . Discrete dynamo events are accompanied by magnetic reconnection and ion heating (see poster by Fiksel et al.), and offer a laboratory analogue for astrophysical dynamos. The dynamo is but one example of the diverse nonlinear phenomena that occur in the RFP. Other examples will also be discussed.

The Madison Symmetric Torus (MST), the RFP at the University of Wisconsin, is the center for experimental RFP research in the US. Beyond studying fundamental physics issues, we seek to make the RFP viable as a power-producing fusion reactor. This requires minimizing magnetic fluctuations in order to minimize energy loss, without adversely affecting the magnetic geometry. Recent results from MST are presented, showing a substantial reduction of magnetic fluctuations, leading to a nine-fold increase in the ability of the plasma to contain energy.

Work supported by the US Department of Energy.

[K20.031] Experiments in Plasma Physics and Fusion Science on the Alcator C-Mod Tokamak

Alcator C-Mod is a compact (R_0=0.67 m), high field (B_t<8.2 T), high-performance, divertor tokamak. Experiments with it investigate the physics of high-temperature (T_i = T_e < 6 keV) magnetically confined fusion-grade plasmas. Plasmas of densities < 1 x 10^21 m^-3 are heated primarily by RF power in the Ion Cyclotron Range of Frequencies (ICRF). The high heating-power density (~5 MW/m^3), the high-Z metal wall (Mo), and the high density are all thought to be necessary elements in a tokamak reactor. Experiments with the plasmas created in this tokamak study a wide range of plasma physics and fusion science. Of primary interest are the following: the study of high plasma toroidal-rotation velocities in excess of 100 km/s that are observed in the absence of any direct momentum input, the creation and study of reduced transport regions, both at the plasma periphery and internal to the plasma, the study of plasma turbulence and transport, especially at the plasma edge and in the very turbulent region just outside the plasma edge (the last closed flux surface), and the study of the interaction of RF waves with hot, magnetized plasma. We find that the RF power can be tailored to drive the toroidal plasma rotation and result in an internal region of reduced transport. As regards the edge transport ``barriers'', we find that pressure gradients in excess of 10 MPa/m are stably sustained. We find that the turbulent transport outside the plasma is ``bursty''. This results in a large particle flux transported across magnetic field lines causing the plasma flow in the edge region to be primarily to the chamber walls rather than along field lines to the divertor volume.

[K20.032] New Physics in Burning Plasmas

Research into the physics of magnetic fusion plasmas has created a physics basis adequate for the design of a tokamak burning plasma facility whose fusion power exceeds the auxiliary power input by a factor Q \geq 10. This poster addresses the question: Will the balance among the diverse physics processes operating in tokamak plasmas change in a reactor-scale device thereby introducing new physics inaccessable to investigation with current facilites? There are three elements of burning plasma physics. (1) Phenomena, such as Alfvén Eigenmodes, associated with plasma heating by energetic \alpha-particles. (2) Self-heating and the resulting self-consistency among thermonuclear heating, temperature profiles, heat diffusivities, current density, and magnetic flux diffusion. And (3) the integration of various plasma and plasma-material interactions in a device large enough to approximately balance transport losses by fusion heating. The poster will present examples from all three elements. Overall, it is concluded that key physics processes which occur in burning plasma devices are inaccessable to experimental investigation in contemporary facilities.

[K20.033] A Major Next Step Experiment in Magnetic Fusion

Excellent progress has been made, and will continue to be made using existing facilities to study the science of high temperature plasmas. However, the nonlinear coupling of plasma turbulence, macroscopic stability, wave particle interactions and plasma boundary physics present in a fusion plasma is a grand challenge for magnetic fusion science that can only be fully addressed in a strongly self-heated plasma. This requires the development of an affordable fusion plasma laboratory facility capable of attaining fusion plasma conditions, and sustaining these conditions so that plasma phenomena can evolve. A national design study of a next step option is underway to develop and assess near term opportunities for addressing the issues identified above. The potential of a compact high field tokamak to address these issues will be discussed.

Work supported by DOE Contract DE-AC02-76CH0 3073.

[K20.034] Global Stability Issues for a Next Step Burning Plasma Experiment

We present analysis which supports the feasibility of a next-step magnetically confined burning plasma experiment. The primary global stability issues are (1) the internal mode associated with the q=1 surface, (2) the energetic particle modes, (3) the presence of edge currents due to the formation of an edge transport barrier in the enhanced confinement regime, and (4) neoclassical tearing modes. We find that (1) the internal mode requires nonlinear analysis including energetic-particle effects, (2) alpha particle driven Alfven modes are expected to be marginally stable in the baseline design, and (3) the nominal self-consistent operating point is stable to external kink modes without a conducting wall, and (4) the predicted critical value for the onset of the NTM is very close to the operating point for the high-field option, and may be mediated by self or active control of seed island width or active island current drive. Advanced operating modes with q > 2 everywhere and high-bootstrap fraction also hold promise and will be discussed.

[K20.035] Characterization of a Dynamic Hohlraum used for High-Energy-Density-Physics applications on Z

The implosion of cylindrical arrays of tungsten wires in a z pinch is used to form a plasma shell, which upon impacting a low-opacity cylindrical target centered on the pinch z-axis, generates x-rays. The high-atomic-number shell traps a fraction of the x-rays produced within the target, and forms a radially converging hohlraum. Such Dynamic Hohlraums (DH) are being developed on Z as intense sources of x-rays for high-energy-density-physics applications [1]. This paper discusses the measured characteristics of one such DH that is currently in use, which generates a 10-TW x-ray pulse through a 2.4-mm diameter aperture, axially centered, above the target. The characteristics are interpreted using 2D radiation-magnetohydrodynamic-codes and an analytical model [2]. [1] T. W. L. Sanford, et al Phys. Plasmas 7, 4669 (2000). [2] S. A. Slutz et al submitted to Phys. Plasmas. *Sandia is a multi-program laboratory operated by the Sandia Corporation, a Lockheed Martin Company, for the U.S. Department of Energy under Contract No. DE-AC04-94AL85000.

[K20.036] Characterization of the 2m ALESPI helicon discharge

The Auburn Linear Experiment for Space Plasma Investigations uses a 2 m long, 10 cm diameter helicon discharge to create the background plasma. In this poster we present a full characterization of the discharge parameters in both argon and helium. RF compensated Lanmuir probes are used to measure electron density and temperature both axially and radially. A 65 GHz microwave interferometer measures cord-averaged density and is used to calibrate the probes. Spectroscopic measurements use Doppler broadening to estimate the cord-averaged ion temperature. Parameter scans in magnetic field strength, fill pressure, and input power and drive frequency to the helicon antenna are reported.

[K20.037] Outreach Coordination for the Plasma Sciences

Outreach for the plasma sciences has adapted to multiple levels and venues for communicating the excitement and possibilities of the field. The internet and web are the most important new media for such public outreach. Nevertheless, a variety of outreach methods and coordination efforts will always be valuable because of their various strengths and weaknesses and the need to address a broad set of goals. This paper reviews ongoing coordination, education and public outreach efforts for the plasma sciences and their interrelation: internet-based web pages [e.g., plasmas.org], interactive tools [e.g., plasma dictionary at http://education-db.llnl.gov/plasma/], and newsgroups [sci.physics.plasma], articles and brochures, educational workshops, exhibits and coordination efforts such as the PlasmaNet [http://www.ias.unu.edu/networks/plasmanet/index.html] and the Coalition for Plasma Science [http://www.plasmacoalition.org].

[K20.038] Gravitation

[K20.039] Toward Causal Set Kinematics

We report on the results of work performed on the kinematic development of causal set quantum gravity. A causal set is a discrete, locally finite, partially ordered set that has been shown to be a viable model for the small-scale structure of spacetime. The relevant projects include work toward the development of dimension estimators for curved spacetimes, the correspondence between geodesic length and the length of the longest chain within a causal set interval, the embedability of causal sets generated via a percolation dynamics, and a sum-over-histories model for the motion of a free particle in a discrete causal spacetime.

[K20.040] The Refractive Relativity Theory

It is suggested that in the general relativity theory the fourth dimension l = ct, the time t is not used as the variable but the light velocity c. With simple calculations it is shown that, e.g., the bending of light by a body of mass is a refraction per Snell’s law - hence the name Refractive Relativity Theory (RRT). As a consequence of the variable c the Hubble redshift is not interpreted as a redshift due to the moving source of the light (Doppler effect) but as a cosmological acceleration of c during the travel time of the light. The force of gravitation is not born out of the time warp but out of the gradient of the light velocity c. The RRT comes up with a theoretical Hubble constant H of 68.65 km/sec/Mpc which is very close to the current observations. It is suggested that if one takes c as the variable instead the time t it makes the concept of the relativity theory more lucid and points to a close affinity to the electromagnetic theory. The gravitational field as a field of a variable velocity of light c has similar features as the Higgs field and therefore the RRT seems to show the way to a theory unifying the gravitational force with the other three forces of electromagnetic nature.

[K20.041] The Maya Project: Numerical Simulations of Black Hole Collisions

The main objective of the MAYA project is the development of a numerical code to solve the vacuum Einstein's field equations for spacetimes containing multiple black hole singularities. Incorporating knowledge gained from previous similar efforts (Binary Black Holes Alliance and the AGAVE project) as well as one-dimensional numerical studies, MAYA has been built from the ground up within the architecture of Cactus 4.0, with particular attention paid to the software engineering aspects of code development. The goal of this new effort is to ultimately have a robust, efficient, readable, and stable numerical code for black hole evolution. This poster presents an overview of the project, focusing on the innovative aspects of the project as well as its current development status.

[K20.042] Neutron Star Redshifts

In a previous paper, a reinterpretation of Maxwell Einstein theory was shown to predict an electromagetic time dilation effect. In a second paper, this electromagnetic time dilation effect was shown to correctly predict the decay lifetimes of muons bound to atomic nuclei. In this current paper, it is shown that using a standard neutron star model, the electromagnetic time dilation effect along with the gravitational time dilation effect, can produce total neutron star redshifts that are as large as the redshifts observered in quasi-stellar objects.

[K20.043] Nuclear Physics

[K20.044] The Production of Neutral Hyperons in Muon Scattering From Protons

We caculate the differential cross sections for the reactions \mu^- +p \longrightarrow \Lambda + \nu_\mu and \mu^- + p\longrightarrow \Sigma^0 + \nu_\mu for incident muon energies from 1 GeV to 10 GeV. Particular use will be made of experimental results via SU(2) and SU(3) relations to make the calculations as model independent as possible..The contributions from the individual form factors will be obtained with a view to isolating contributions from the pseudoscalar form factor. The results will be compared to those from the corresponding electron reactions.

[K20.045] The Inclusive Antineutrino Reaction on ^12C

Cross sections are obtained for the reactions \bar\nu_e + ^12C\longrightarrow e^+ + X and \bar\nu_\mu + ^12C\longrightarrow \mu^+ + X from threshold to 300 MeV. The results will be calculated via a phenomenological model. The cross sections will be compared with corresponding neutrino inclusive cross sections to determine what might be learned about the model used here. The possibility of observing these reactions will also be discussed.

[K20.046] Hartree-Fock vs Shell Model Analysis of the Binding Energies of 1f_7/2 Nuclei

We developed a Hartree-Fock code to calculate the ground state (.g.s) energies using realistic shell model nuclear forces (e.g. [Nucl. Phys. A523, 325 (1991)] and [Ann. Rev. Nucl. Part. Sci. 38, 29 (1988)]). In order to include as many correlations as possible we break almost all symmetries including rotational symmetry, time reversal and charge invariance. The binding energies results for 1f_7/2 nuclei (^40Ca to ^56Ni) are compared with the results of full shell model calculations based on the exponential convergence method [M. Horoi et al, Phys. Rev. Lett. 82, 2064(1999)]. The effect of restoration of the broken symmetries is also discussed.

[K20.047] Rabi, the proton magnetic moment, and the ‘2-wire' magnet, 1931-34

With the assistance of Gregory Breit, I.I. Rabi, at Columbia University, worked out in 1931 a method to determine the spin (not the magnetic moment) of atomic nuclei by deflecting an atomic beam of the isotope in question in a weak, but long, inhomogeneous magnetic field. Crucial to this method was that it required no exact knowledge of that field. When the sensational result -- µ_p = 2.5µ_Bohr(m_e/m_p) -- from Otto Stern's deflection of a beam of hydrogen molecules in a strong magnetic field became known late in 1932, its confirmation by another laboratory, preferably by another method, seemed urgent. No one else had the refined technique to reproduce Stern's experiment. But because the hydrogen electronic wave function was known, the Breit-Rabi technique was susceptible of extension in this case to the measurement of the magnetic moment of the proton - - but only with accurate knowledge of the magnetic field and field gradient traversed by the atomic hydrogen beam. To this end Rabi introduced the '2-wire' magnet, producing a weak field and uniform gradient that could be calculated rather than measured. This field configuration quickly came to be used in all magnetic deflection experiments in Rabi's laboratory, first as produced directly by electric currents, and subsequently as emulated in iron electromagnets in order to achieve the higher magnetic fields required by molecular beam magnetic resonance experiments from 1937 onward.

[K20.048] Few Body Systems

[K20.049] Two body Dirac Equations from Constraint Dynamics for Nucleon-Nucleon Scattering.

We examine the nucleon-nucleon scattering problem by formulating this two-body problem in terms of two-body Dirac equations derived from Dirac's constraint dynamics to. This formalism has been successfully applied to relativistic two-body bound states in quantum electrodynamics and quantum chromodynamics. By way of a Pauli reduction of the constraint two body Dirac equations we can obtain a relativistic Schrödinger like equation. The Dirac equations are covariant and this allows us to introduce potentials that have arbitary Lorentz transformation properies. We include potentials that transform like pseudoscalar, vector, and scalar interactions. We include three mesons exchanges for each type. Since these two-body Dirac equations can be reduced to Schrödinger like forms we find it convenitent to use the variable phase method developed for the nonrelativistic Schrödinger equation by Colgero to determine the phase shifts. We present preliminary results in this paper.

[K20.050] Scattering State Spectroscopy of the Reaction Li* (3p) + H2 - LiH (v²= 1, 2, J² ) + H

We did laser pump-probe far-wing scattering experiments to study the photochemical reactions Li* ( 3p) + H2 - LiH (v"= 1, 2, J") + H. We have observed the Li (3p) + H2 - LiH + H reaction . The rotational state distribution of the LiH product for excitation in the red wing is identical to that found in the blue wing region, and it does not show any preference to high or low rotational states and no asymmetry is observed in the reactive to nonreactive branching ratio. We have shown different possibilities for the reactive and nonreactive collisions and give a tentative explanation of the reaction mechanism using the highly accurate ab initio potential energy surfaces. We also show that the harpooning model cannot be used to explain the reaction mechanism in the Li* + H2 collision for all the atomic states from Li(2s) to Li(3d), that is there occurs no long range electron transfer from the metal atom to the hydrogen molecule.

[K20.051] The Relativistic N-body Problem in a Separable Two-Body Basis

We use Dirac's constraint dynamics to obtain a Hamiltonian formulation of the relativistic N-body problem in a separable two-body basis in which the particles interact pair-wise through scalar and vector interactions. The resultant N-body Hamiltonian is relativistically covariant. It can be easily separated in terms of the center-of-mass and the relative motion of any two-body subsystem. It can also be separated into an unperturbed Hamiltonian with a residual interaction. In a system of two-body composite particles, the solutions of the unperturbed Hamiltonian are relativistic two-body internal states, each of which can be obtained by solving a relativistic Schrödinger-like equation. The resultant two-body wave functions can be used as basis states to evaluate reaction matrix elements in the general N-body problem. We prove a relativistic version of the post-prior equivalence which guarantees a unique evaluation of the reaction matrix element, independent of the ways of separating the Hamiltonian into unperturbed and residual interactions. Since an arbitrary reaction matrix element involves composite particles in motion, we show explicitly how such matrix elements can be evaluated in terms of the wave functions of the composite particles and the relevant Lorentz transformations.

[K20.052] The Parker-Sochacki Method--A Powerful New Method for Solving Systems of Differential Equations

The Parker-Sochacki Method--A Powerful New Method for Solving Systems of Differential Equations

Joseph W. Rudmin (Physics Dept, James Madison University)

A new system of solving systems of differential equations will be presented, which has been developed by J. Edgar Parker and James Sochacki, of the James Madison University Mathematics Department. The method produces MacClaurin Series solutions to systems of differential equations, with the coefficients in either algebraic or numerical form. The method yields high-degree solutions: 20th degree is easily obtainable. It is conceptually simple, fast, and extremely general. It has been applied to over a hundred systems of differential equations, some of which were previously unsolved, and has yet to fail to solve any system for which the MacClaurin series converges. The method is non-recursive: each coefficient in the series is calculated just once, in closed form, and its accuracy is limited only by the digital accuracy of the computer. Although the original differential equations may include any mathematical functions, the computational method includes ONLY the operations of addition, subtraction, and multiplication. Furthermore, it is perfectly suited to parallel -processing computer languages. Those who learn this system will never use Runge-Kutta or predictor-corrector methods again. Examples will be presented, including the classical many-body problem.

[K20.053] Particle Theory

[K20.054] Semi-Classical Models for Virtual Antiparticle Pairs

Virtual particle-antiparticle pairs of massive elementary particles are predicted in Quantum Field Theory (QFT) to appear from the vacuum and annihilate each other again within their Heisenberg lifetimes \hbar/4mc^2. In this work, semi-classical models of this process -- for the cases of massive leptons, quarks, and the massive weak bosons W and Z -- are constructed. It is shown that the dynamical lifetime of the particle- antiparticle system in each case equals the Heisenberg lifetime to good approximation, and obeys appropriate quantization conditions on the field fluctuation action. In other words, the dynamical lifetime of the semi-classical model agrees with QED and QCD to good approximation. But the formula for the dynamical lifetime in each model includes the force strength coupling constant (e in the lepton case, \alpha_s(q^2) in the quark cases), while the Heisenberg lifetime formula does not. Observing the agreement of the Heisenberg and dynamical lifetimes, we may derive the QED and QCD coupling constants in terms of \hbar, c, and numerical factors only.

[K20.055] NEO-RITZIAN THEORY: A THIRD SUPPLEMENTARY INDEX OF WORK BY THE AUTHOR

Bull. Am. Phys. Soc. 30, 406, 755 (1985); 34, 1146 (1989); 37, 966f (1992); 38, 968 (1993); 39, 1255f (1994); 40, 559, 994 (1995); 42, 927, 1129 (1997); 43, 1090 (1998); 44, 1255, 1626 (1999). Galilean Electrodynamics: 7, 59 (1996); 8, 16, 30, 56 (1997); 9, 100 (1998). Hadronic Journal: 14, 501 (1991); 17, 551 (1994); 18, 195 (1995); 20, 301 (1997). Hadronic Journal Supplement: 5, 103 (1990); 10, 315 (1995); 14, 409 (1999). Physics Essays: 4, 561 (1991); 5, 220 (1992); 7 355 (1994); 10, 198, 394 (1997); 11, 504 (1998); "Ampère Force Uncontaminated by Ampère's Disproven Third Law" (received 7 October 1999); "True Transformations Relativity vs. Material Relativity" (received 31 October 2000). Monograph: Annex to Unified Theory of Ether, Field and Matter, ix + 161 pp. (Ether: Vacuum. Pub. data: Books in Print, R. R. Bowker Co.) Note: this abstract corrects and updates the garbled D3-32 on page 1090 of BAPS Vol. 43 (1998).

[K20.056] Masses of the Sub-Nuclear Particles

The CBM model of the nucleus has been expanded into the realm of particle physics to attempt to predict the masses of the sub nuclear and elementary particles. This effort assumes that the masses, (as predicted by CBM) of the "up" quark at 237.31 MeV/c2 and the "dn" quark at 42.39 MeV/c2, are correct and attempts to establish a mathematical relationship that explains as many of the existing quarks and lepton masses as possible. Only the mass of the Top quark (175 GeV/c2 ) is inconsistent with this new scheme. The new mathematical algorithm, which relies heavily on the concept of geometric means, both within a generation and between generations, predicts two new generations of quarks and leptons. One of these new generations predicts quarks that are much lighter than the up and dn quarks and contains the electron as its lepton. The other predicted generation is heavier in mass than the generation containing t and b. This new massive generation contains a massive lepton of 27.0 - 27.4 GeV/c2, which this model calls the gluon. Also in this massive generation is a massive "up-like" quark dubbed "left" at 63 - 67 GeV/c2 and a massive "dn-like" quark dubbed "right" at 42.4 GeV/c2. Convergence of quarks and leptons takes place at about 424 GeV/c2. The key to this new model is finding a 7.5-7.6 MeV/c2 lepton for the hypothesized "up/dn" generation along with confirmation of the John Simpson neutrino.

[K20.057] Universe as an Expanding Phase Boundary in a Four-Dimensional Euclidean Space

It is proposed that space is a four-dimensional Euclidean space with universal time. Originally this space was filled with a uniform substance, pictured as a liquid, which at some time became supercooled. Our universe began as a nucleation event initiating a liquid to solid transition. The universe we inhabit and are directly aware of consists of only the three-dimensional expanding phase boundary. Random energy transfers to the boundary from thermal fluctuations in the adjacent bulk phases are interpreted by us as quantum fluctuations. Fermionic matter is modeled as screw dislocations, gauge bosons as surface phonons. Minkowski space emerges dynamically through redefining the local time to be proportional to the spatial coordinate perpendicular to the boundary. Other features include a geometrical quantum gravitational theory, and a natural mechanism to explain quantum measurement.

[K20.058] Beam Physics, Storage Rings, Radiation Sources and Diagnostics

[K20.059] Self-Focused Electron and Positive-Ion Beams Produced by Heated or Cooled Pyroelectric Crystals in Dilute Gases

Self-focusing, spatially stable, variable energy electron and positive-ion beams accelerated from LiNbO_3 crystal surfaces in dilute gases after the crystal has been heated and returned to room temperature have been observed. A 4 mm dia x 10 mm cylindrical LiNbO_3 crystal in <10 mtorr of dry N_2 is heated from the + z base to 160^0 C and allowed to cool to room temperature after which spatially-stable electron beams are produced. A ZnS screen was placed at the focal length (16 cm) of the crystal and photographs of the beam spot were taken at different pressures. A 100 \mum surface barrier electron detector was used to determine the maximum electron beam energy (147keV). A similar crystal in 5x10^-6 torr of dry N_2 when heated from the –z base accelerated N_2^+ ions up to 113 keV from the +z base on cooling. The dynamic behavior of the electron beam as pressure changes will be demonstrated on a CD rom and laptop.

1 J.D. Brownridge, S. M. Shafroth, D. Trott, B. Stoner, W. Hooke (Applied Physics Letts, Jan 22,01)

2. J.D. Brownridge, Nature (London) 358, 278 (1992)

3. J.D. Brownridge, and S. Raboy, J. Appl. Phys. 86, 640 (1999)

[K20.060] Intense Muon Beams and Neutrino Physics

High intensity muon beams are needed in exploring lepton flavor violating muon processes, lower energy experiments and neutrino factories as the stepping phase towards building higher energy muon colliders. We present an overview and example of a possible muon storage ring based neutrino factory (e.g. at BNL with detectors e.g. at Sudan). Physics with low energy neutrino beams based on conventional Horn Facilities and neutrino factory based on muon storage- rings are described and compared.

[K20.061] Lithium metal for x-ray filters and refractive optics

Lithium is the most x-ray transparent solid element. Lithium is very stable in dry air with a dew point below -50 C or so, but as the humidity increases lithium starts to react with the air's nitrogen and oxygen. Under usual laboratory conditions a shiny piece of lithium metal becomes a white powder within the hour, preventing lithium's widespread use in x-ray work.

Use of lithium as a window for pulsed x-rays demands that lithium withstands corrosion in open air for at least 15 minutes. Protection by a one micron layer of parylene turns out to be enough. Although parylene absorbs soft x-rays 12 times more than lithium, the parylene layer can remain in place for the window application.

Lithium is also ideal for refractive x-ray lenses. We are evaluating the performance of such lenses with 10 keV photons from the MHATT-CAT beam line at the Advanced Photon Source. These measurements are in progress: the paper will show the results from these measurements as available.

[K20.062] Optical Spectroscopy and Stimulated Emission of Dysprosium-doped Tungstates

Rare-earth ion-doped tungstate materials have been intensively investigated for laser development for lidar applications. The tungstate materials in many different compositions have a large x(3) Raman scattering effect and can be used in various laser experiments and developments. We are currently interested in the development of a visible laser, which can be doubled to the 270-320 nm for the remote sensing of ozone in the atmosphere. Recently, a new visible stimulated-emission at 574 nm in Dy-doped KGd(WO_4)_2 has been reported. The stimulated emission line is assigned to the ^4F_9/2 to ^6H_13/2 transition of Dy^3+ activators. The peak emission cross-section of this channel is ~5.4x10^-20 cm^2 with our spectroscopic parameters. The lifetime at ^4F_9/2 and the branching ratio of the ^4F_9/2 to ^6H_13/2 stimulated emission channel are ~160 \mus and ~0.69, respectively. Details of inter-manifold and inter-Stark transitions and emission properties of Dy-doped KGW will be discussed.

[K20.063] Optical Spectroscopy of Europium doped Gallium Nitride prepared by Solid Source Molecular Beam Epitaxy

Thin Film Electroluminescence Displays (TEFL’s) are all solid-state devices and offer several advantages over well known LCD’s including increased brightness and viewing angle. We are currently investigating Eu doped GaN as a potential red phosphor for TEFL display applications. Eu doped GaN films were grown by solid source molecular beam epitaxy on Si (111) substates. The material was optically characterized through temperature dependent emission spectroscopy using a He-Cd laser at 325 nm for above band gap excitation. A strong red emission was obtained at ~622 nm, which corresponds to an Eu^3+ inner 4f-shell transition from the ^5D _0 to ^7F_2 state. A temperature dependent study of the red Eu^3+ line showed that the integrated emission intensity decreased by roughly a factor of 20 between 77K and room temperature. On the contrary, the emission lifetime changed only slightly (~10-20non-radiative decay processes are small. Therefore, the observed thermal quenching of red Eu emission is assigned to a strongly temperature dependent pumping process.

[K20.064] The application of OTR-DR interferometry to the measuremement of the divergens of low energy (10MeV) electron beam.

To avoid to some extent the undesirable scattering effect of the first foil in the traditional Optical Transition Radiation Interferometer - OTRI we propose a perforated foil as the first foil of the OTRI. Many holes of reasonable size and spacing can be made in this foil. In this case a substantial fraction of the beam electrons will not be scattered and the fraction of beam electrons passing through the holes will produce Optical Diffraction Radiation - ODR. The total coherent radiation produced will be the superposition of radiation from unscattered electrons ( the ODR from the holes in the first foil - OTR from second foil) and OTR from heavily scattered electrons. By choosing appropriate foil spacing and bandpass of the radiation, interference fringes in the light angular distribution (unscattered beam) are visible above the nonfringed background of light produced by the heavily scattered portion of beam. Such a system is planned to characterize the beam used the University of Maryland Infrared Free Electron LASER ( MIRFEL) experiment. Calculations demonstrate capability of the method to measure initial beam angular spread of order of milliradians for beam energies less than 10 MeV.

[K20.065] Measurement of the Divergence of Low Energy Electron Beams Using OTR - ODR Interferometry

Optical Transition Radiation Interferometry has been shown to be a useful diagnostic to measure the divergence of low emittance electron beams with energies greater than 15 MeV. A limitation of this method for lower energies is scattering in the first foil of the interferometer. To mitigate this effect we propose to use a perforated front foil. Electrons passing through the holes will produce Optical Diffraction Radiation (ODR). The total coherent radiation produced from the first and second foils will be ODR and OTR from unscattered electrons and OTR from heavily scattered electrons. By choosing the appropriate inter-foil spacing and bandpass filter, interference fringes in the light produced by unscattered electrons will be visible above the background light from the scattered portion of beam. Calculations show that the method is capable of measuring an initial beam divergence of the order of a few milliradians for beam energies less than 10 MeV.

[K20.066] General Physics

[K20.067] Macroscopically symmetric domain configurations in ferroic crystals

The characteristic feature of ferroic crystals - a polydomain structure - allows one by suitable driving forces to produce domain configurations exhibiting a symmetry on a macroscopic scale. Properties of such processed ferroic crystals can be highly specific; under certain circumstances their domain configurations can be relatively stable. A particular example represent engineered rhombohedral single crystals of relaxor based ferroelectric Pb(Zn_1/3Nb_2/3)O_3-PbTiO_3 which are reported to have much enhanced piezoelectric and dielectric properties and to be almost fatigue-free. These phenomena are probably related to the supposed macroscopic symmetry \mathsf4mm. However, the actual domain structure has not been fully analyzed yet. We demonstrate a theoretical method how to derive possible coherent domain configurations, i.e. those configurations that are macroscopically symmetric and involve all domain states belonging to a single orbit of the respective point group. Such states will have equal free energy in an external field invariant under the point group. As an illustration, we give results for some multiferroic materials. Also, we determine driving forces that can induce coherent domain configurations.

[K20.068] Modeling the effect of oxygen on reverse annealing behavior of proton and neutron irradiated silicon detectors

For tracking applications at future CERN Large Hadron Collider (LHC), the long term operation of silicon detectors in the extremely high fluences of radiation over a ten year period is a serious problem. One of the most important puzzles in LHC project is "why oxygen is beneficial to radiation hardness of silicon detectors when irradiated with protons?". From experimental results it is clear that increase of negative space charge during the period after irradiation (reverse annealing) has been linked to clustered defects and from indirect evidence releasing of interstitial is more probable in reverse annealing. With these assumptions a theoretical model is presented by using exchange charge model and kinetic equation for describing the experimental results. The results show that for silicon containing oxygen the core of cluster is surrounded by a belt of VO defect center, which it's radius is much larger in proton irradiated silicon and it's concentration depends on the concentration of oxygen in the sample. So if an interstitial related defect is responsible for reverse annealing then this effect in proton irradiated samples can be reduced and delayed by trapping of interstitials in the VO clustered centers. This is also consistence with experimental results that show the activation energy of reverse annealing is the same for standard and oxygenated silicon detectors.

[K20.069] Pulse-Coupled Oscillators on Disordered Networks

We consider the behavior of populations of pulse-coupled oscillators embedded on both random networks and lattices, investigating the effects of network disorder on the collective behavior of the oscillators. We provide a meaningful notion of this disorder by introducing the idea of a network temperature. For several different topologies, it is observed that a fully-synchronized network state gives way to a self-organized critical state at a critical level of network disorder.

[K20.070] Post-deadline Posters

[K20.071] SOC, Turbulence and the Origin of Scaling in an Open, Driven Natural Plasma Confinement System

The earth's magnetosphere is an example of a naturally occurring extended, open, driven, dissipative plasma confinement system. As such it is possible that, in addition to plasma-specific physics, it may exhibit behaviour generic to such potentially complex systems. Evidence for one such type of behaviour, self-organised criticality (SOC), has been presented by several authors, based partly on the existence of an extended scale-free region in the probability density of bursts in the auroral electrojet indices (AE,AU and AL), a proxy for energy dissipation out of the magnetosphere. We use in-situ measurements from the NASA WIND spacececraft to determine the PDF of burst durations D(T) for the energy supplied via the solar wind Poynting flux to the magnetosphere. We show that the scale free region in D(T) for AU and AL is also present in D(T) for the solar wind driver [Freeman et al., Geophys. Res. Lett., 27, 1087 (2000)].

The distribution of waiting times D(\tau) between energy release events in turbulent media has been proposed [Boffetta et al., PRL, 83, 4662 (1999)] as a possible discriminator between SOC and non-SOC models. We thus also examine the set of PDFs of burst lifetime D(T), waiting time D(\tau) and magnitude D(s) to constrain the range of possible models for the origin of scaling in the solar wind.

We conclude by discussing the extent to which Boffetta et al's test can really discriminate between SOC and other phenomena [Freeman et al., PRE, 62, 8794 (2000)].

For further information

[K20.072] Statistical Complexity and Geophysical Time Series: Opportunities and Pitfalls

The methods so far used in mathematical physics to describe patterns in nature are usually based on an assumption of near periodicity (e.g. Fourier methods) or near total stochasticity (e.g. equilibrium statistical mechanics). Many systems, however, lie between the limits of a periodic crystal and and ideal gas. Recently, the concept of statistical complexity has been further developed [e.g. Badii and Politi,"Complexity", Cambridge University Press, 1997] to bridge this gap and provide the most compact possible predictive description of an observed time series. In view of the current interest in self-organised criticality and complexity in the magnetosphere, we are motivated to ask whether this concept can be applied to magnetospheric data and so by extension to other such intrinsically complex, many degree-of- freedom natural systems. We report on the calculation of statistical complexity for model systems thought to represent magnetospheric dynamics.

For further information

[K20.073] Search for a fermiophobic Higgs boson decaying to WW with the L3 detector at LEP

A search is performed for a Higgs boson decaying into W bosons, using the data collected by the L3 detector at center-of-mass energies up to 209 GeV at LEP. The process e^+e^- \rightarrow HZ \rightarrow f\bar\mathrmf WW is considered for several decay channels of the Z and W. Limits on the rate of the Higgs boson decay into W bosons as a function of the Higgs mass and mass limits for a standard fermiophobic Higgs are presented.

[K20.074] Search for a fermiophobic Higgs boson decaying to \gamma\gamma with the L3 detector at LEP

A search is performed for a Higgs boson decaying into photons, using the data collected by the L3 detector at center-of-mass energies up to 209 GeV at LEP. The process e^+e^- \rightarrow HZ \rightarrow f\bar\mathrmf \gamma\gamma is considered for all decay channels of the Z. Limits on the rate of the Higgs boson decay into photons as a function of the Higgs mass and mass limits for a standard fermiophobic Higgs are presented.

[K20.075] Techniques and development of a object-based distributed analysis framework

New experiments in several disciplines including high energy and astrophysics require analysis of very large datasets which can best be handled with distributed computation. We present the design and development of a prototype framework using Java, C++, and Objectivity. Our framework solves such analysis-specific problems as selecting event samples from large distributed databases and producing variable distributions from such datasets. Examples from the successful application of the prototype to the analysis of data from the L3 experiment will also be presented.

[K20.076] Construction of An Approximate Periodic Solution to a Modified Lewis Equation

We investigate the periodic solutions of a modified Lewis equation^1,

x+x^3=3D\upsilon [1-\left| x\right| ] \'x \labelEq. 1

In Eq. (1), \upsilon is a small and positive parameter and the ''dots'' indicate time derivatives. Note that the nonlinear term on the right-side contains the absolute value of the dependent variable. Also, the left-side has no linear term and, consequently, when \upsilon =3D0, the equation is still nonlinear. Using the method of harmonic balance^2, analytic approximation to the unique periodic solution is calculated. We also give a general discussion of the properties of the solutions to Eq. (1) in phase-space.

[K20.077] Missing transverse energy in LHC/CMS

Reconstruction of missing transverse energy will be especially challenging at the Large Hadron Collider because of the high center-of-mass energy, high luminosity, and large number of interactions per crossing. We present in this talk work done by members of the CMS collaboration on understanding how these difficulties will affect trigger rates and our ability to do physics, and on to overcome them.

[K20.078] Searching for a Higgs that decays to two tau's with the CMS Detector

We report on a simulation of neutral Higgs decay to 2 tau's, in the CMS detector. This study uses the Pythia generator, CMSIM, the geant simulation of the CMS detector, and ORCA, the object oriented reconstruction for CMS analysis. We include the effects of an average pileup of 17.3 events expected in a realistic situation.

[K20.079] Discovery of a 450 Hz QPO from the Microquasar GRO J1655-40 with RXTE

We report the discovery with the proportional counter array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE) of a 450 Hz quasiperiodic oscillation (QPO) in the hard X-ray flux from the galactic microquasar GRO J1655-40. This is the highest frequency QPO modulation seen to date from a black hole. The QPO is detected only in the hard X-ray band above \sim 13 keV, and is seen preferentially at times when a \sim 300 Hz QPO is observed predominantly in the soft X-ray range. We show that these two QPO appear simultaneously, thus demonstrating the first detection of a pair of high frequency QPO in a black hole system. Prior to this, pairs of high frequency QPO have only been detected in neutron star systems. GRO J1655-40 is one of only a handful of black hole systems with a good dynamical mass constraint. The \sim 7 M_ødot mass implies an innermost stable circular orbit (ISCO), assuming a non-rotating hole, of 64 km. The radius of an orbit with a frequency of 450 Hz is significantly less than this (\sim 49 km), indicating that if the modulation is caused by Kepler motion, the black hole must have appreciable spin. Moreover, if the modulation is caused by oscillation modes in the disk or Lense-Thirring precession, then this would also require a rapidly rotating hole. We briefly discuss the implications of our findings for models of X-ray variability in black holes and neutron stars.

[K20.080] The Water Purification Systems for the Sudbury Neutrino Observatory.

The Sudbury Neutrino Observatory will measure the flux and energy spectrum of electron neutrinos and, independently, the combined flux of all active flavors of neutrinos. Radioactive contaminants are a potential source of background to the observation of these neutrinos. For example, \gamma-rays with an energy greater than about 2.2 MeV can photodissociate the deuteron. This is indistinguishable from the neutral current dissociation of the deuteron-the main signal to measure the total flux of active neutrinos from the sun. In addition, electrons and photons greater than a few MeV will be backgrounds to the measurement of the charged current reaction-the main signal to determine the flux of electron neutrinos from the sun. Thus, low energy radioactive contaminants in the detector must be controlled to be low and their levels must be well understood. The SNO water purification and assay systems have been designed to reduce and assess radioactive backgrounds. An overview of the water purification systems will be discussed.

[K20.081] Radiative Blast Waves

We simulate experiments performed with the Falcon laser at Lawrence Livermore National Laboratory to generate strong blast waves expanding in cylindrical geometry of relevance to astrophysics. In particular, we are interested in producing and modeling radiative shocks. Our goal is to develop a laboratory setting for studying radiative shocks of relevance to supernova remnants. In previous work we have demonstrated that it is possible to generate radiative shocks in the laboratory. In additions, we have shown how we can determine the energy-loss rate of the shock from the blast wave evolution using a simple analytic method that is independent of the details of radiative cooling and is scalable to both the laboratory and astrophysical blast waves. Our current work deals with instabilities associated with radiative blast waves and their application to the laboratory and to astrophysics. We examine some of the previous work done in the area of radiative instabilities in supernova remnants and discuss the challenges of adapting this work to the laboratory setting.

[K20.082] Pileup event subtraction at the BNL muon g-2 experiment

The BNL muon g-2 experiment has completed the analysis of 1999 data. One of the most important systematic error contribution to the g-2 precession frequency was positron pileup. Pileup events occurred when two decay positrons hit the detectors within their time resolution. These events carry incorrect phase and energy information. Various approaches took place in the analysis for pileup. One of them was to extract the pileup information from the data itself which made the pileup subtraction possible. This subtraction method may also be useful to the experiments run with high intensity if a similar data taking procedure exists.

[K20.083] Lifetime Measurements in ^84Zr

Using the reaction ^58Ni(^32S,\alpha\,2p), high angular momentum states in ^84Zr were populated. A Ta backing was used as the stopping material for the recoiling nuclei. \gamma-\gamma coincidences and evaporated charged particles were detected using the arrays GAMMASPHERE and MICROBALL. Lifetimes and sidefeeding times of more than 20 levels were measured using the Doppler Shift Attenuattion method. The deduced quadrupole moment for the yrast band is quite constant around a value of 2.2 \,eb up to a spin of I=28 \hbar . It is the first time that quadrupole moments have been determined up to so a high spin of a ND band in the A \approx 80 region.

[K20.084] Electron-Fluxon Approach to the Quantum Hall Effect

Experimental data by Willett et al.(R. Willett et al.), Phys. Rev. Lett. 59, 1776 (1987). show that the Hall resistivity \rho_xy at the extreme low temperatures has plateaus at fractional occupation ratios (2D electron density / fluxon density) \nu with odd denominators, where the longitudinal resistivity \rho_xx (nearly) vanishes. The plateau heights are quantized in units of h/e^2. Each plateau is material- and shape-independent and indicates the stability of the superconducting state. The same data show that \rho_xy is linear in B at \nu=1/2, where \rho_xx has a small dip, indicating a Fermi-liquid-like state with a different kind of stability. We develop a microscopic theory of the quantum Hall effect in analogy with the theory of the high temperature superconductivity, regarding the fluxon as a quantum particle with half spin and zero mass. Each Landau level, E=(N+1/2)\hbar ømega_0, ømega_0=eB/m, has a great degeneracy. Exchange of a longitudinal phonon can generate an attractive transition between the degenerate states. The same exchange can also pair-create electron-fluxon composites, bosonic and fermionic depending on the number of fluxons. The model accounts for the energy gap at each plateau, ensuring the stability of the superconducting state.

[K20.085] Scintillation Efficiency of Liquid and Solid Neon: Preliminary Experiments for the CLEAN Solar Neutrino Detector

Recently, a neutrino detector (CLEAN) has been proposed that employs either liquid helium or liquid neon as a scintillator to detect neutrino-electron scattering events and thus measure in real time the low energy solar neutrino flux. Liquid helium and liquid neon are attractive choices for such a detector because they can be purified very efficiently using distillation and cold traps, essentially eliminating backgrounds in the detector caused by radioactive impurities. Because of its higher electron density, a neon based version of CLEAN could be made significantly smaller than a similar helium based detector. While the light yield from charged particle induced scintillations in liquid helium has previously been measured, to our knowledge, the light yield from liquid neon has not. Knowledge of the light yield from neon is necessary to determine how it can be used as a scintillator. We report measurements of the scintillation efficiency of liquid and solid neon for both alpha and beta radiation and compare it to that of liquid helium.

Part K of program listing