Session hTupP3 - Poster Session: Education and Outreach and Undergraduate Research.
POSTER session, Tuesday afternoon, November 18
South Hall, Convention Center

[hTupP3.01] Outreach Activities for Plasma Science

The need for communication beyond experts from subfields of scientific inquiry has been long identified. In response to this need, new outreach activities for plasma science have begun to take shape and grow. One example of this increase in activity is the formation of the Coalition for Plasma Science. The focus of the Coalition's efforts is to enhance the understanding and support for plasma science in the scientific community, the education community, business and the general public. One of the Coalition's first activities was to coordinate the assembly of an eight panel exhibit entitled "Plasmas: Science and Technology for the 21st Century". The formation of the Coalition and the display will be described and some possible future activities will be outlined.

[hTupP3.02] Fusion Science Outreach at the MIT Plasma Science and Fusion Center

Educational Outreach at the MIT Plasma Science and Fusion Center is organized and energized by volunteers working together to increase the public's knowledge of fusion and plasma-related experiments. The PSFC holds a number of outreach activities throughout the year, such as Middle and High School Outreach Days. Included in these days is a demonstration of how magnets affect plasma using the ``Plasma Demo," an educational tool which will be on display for the first time outside the MIT area. Also featured is ``C-Mod Jr.," a video game which helps students discover how computers manipulate magnetic pulses to keep a plasma confined in the C-Mod tokamak for as long as possible. The PSFC maintains a Home Page on the World Wide Web, which can be reached at HTTP://PFC.MIT.EDU.

[hTupP3.03] Having Fun with Physics at the MIT Plasma Science and Fusion Center

MIT Plasma Science and Fusion Center staff and students are convinced that students learn best not by studying but by doing. This was the impetus behind a group of MIT graduate students who created Cambridge Physics Outlet, a PSFC spin-off company dedicated to creating hands-on experiments. The same impulse fostered the award-winning Mr. Magnet Program, a traveling presentation which uses a hands-on strategy to engage elementary school children. A number of ingenious experiments will be demonstrated. The PSFC maintains a Home Page on the World Wide Web, which can be reached at HTTP://PFC.MIT.EDU.

[hTupP3.04] Educational and Outreach Programs at HU Center for Fusion Research and Training

This abstract was not submitted electronically.

[hTupP3.05] New Education/Outreach Materials from CPEP

The Contemporary Physics Education Project (CPEP) introduces two variations of its successful teaching chart, "FUSION - Physics of a Fundamental Energy Source". The first new version is the POSTER size chart - 53x75 cm. This chart is intended for office or bulletin board display. The second is the laminated version of the NOTEbook (or student) size chart (43x28 cm). This semi-indestructible version also finds use as a placemat. These new materials complement the WALLsize FUSION chart (107x150 cm) and the regular (un-laminated) NOTEbook chart introduced last year. To promote effective classroom use of its educational materials, CPEP offers workshops for high school and college science teachers, including workshops presented at annual DPP and AAPT meetings. Sometimes these workshops are held in conjunction with other groups such as the Space Science Institute. For more information about CPEP, a not-for-profit corporation of teachers, educators and physicists, visit (http://pdg.lbl.gov/cpep.html).

[hTupP3.06] General Atomics Sciences Education Foundation Outreach Programs

Scientific literacy for all students is a national goal. The General Atomics (GA) Foundation Outreach Program is committed to playing a major role in enhancing pre-college education in science, engineering and new technologies. GA has received wide recognition for its Sciences Education Program, a volunteer effort of GA employees and San Diego science teachers. GA teacher/scientist teams have developed inquiry-based education modules and associated workshops based on areas of core competency at GA: Fusion -- Energy of the Stars; Explorations in Materials Science; Portrait of an Atom; DNA Technology. [http://www.sci-ed-ga.org]. Workshops [teachers receive printed materials and laboratory kits for ``hands-on" modules] have been presented for 700+ teachers from 200+ area schools. Additional workshops include: University of Denver for Denver Public Schools; National Educators Workshop; Standard Experiments in Engineering Materials; Update '96 in Los Alamos; Newspapers in Education Workshop (LA Times); American Chemical Society Regional/National meetings, and California Science Teachers Association Conference. Other outreach includes High School Science Day, school partnerships, teacher and student mentoring and the San Diego Science Alliance [http://www.sdsa.org].

[hTupP3.07] Fusion Sciences Education Outreach in the Middle Schools, an Unplanned Case Study

Before bringing a class to General Atomics (GA) for the DIII--D educational tour, the teacher is provided with pre-tour materials which include a videotape, curriculum notebook and fusion poster. These materials are used in the classroom to familiarize students with fusion concepts before the tour. This presentation will focus on the results of projects of 7th grade students of Chula Vista Junior High School (a magnet school for performing arts with a majority of Hispanic students). The assignment given by Physics Teacher Caryn Hoffman to her students prior to the tour was to focus on one or two of the DIII--D tour guides, ask questions relating to their careers in science and then prepare a presentation based on their interviews and their tour experience. The completed projects were very diverse -- calendars, comic strips, newspapers, plays, and board games were some of the media the students used. Tour guides selected by the students ranged from physicists, designers and computer support personnel. Project results reflected a surprisingly good understanding of fusion science concepts. Subsequent classroom interviews with the students demonstrated an overall increase in science interest and a specific interest in plasma and fusion research.

[hTupP3.08] Advancing Precollege Science Education

The General Atomics Fusion Group Education Outreach Program, with support from DOE, has been active in reinforcing topics in contemporary science education and advancing concepts in plasma physics and fusion science to many middle and high school students. This requires active involvement among educator, scientist, and student. The outreach program strives for active participation in the learning process via stimulating and memorable demonstrations and interactive displays. It also provides a videotape on fusion and curricular material to teachers for classroom discussion covering topics such as the electromagnetic spectrum, radiation, energy, magnetic and inertial confinement fusion, CAD, data acquisition and computers, and energy. The program is continuing its direct involvement with area educators to help shape material and demonstrations which are grade appropriate, relevant, provide hands-on activities, and stimulate thinking and discussion. Recent program enhancements include increased material development, tour station upgrades, scientist visits to classrooms, increased web activities, and work towards completion of an interactive CD-ROM. Examples from curricular material, student activities, and demonstration stations will be discussed.

[hTupP3.09] Coordination for Plasma Science and Technology

There are multiple levels and venues for communicating the excitement and possibilities of plasma science and technology to a broader audience. The internet and web are the most important new media for such public outreach. Nevertheless, a plurality of methods will always be needed because of the various strengths and weaknesses of each venue. Similarly, a plurality of coordination efforts is needed to adequately address recognized education and public outreach needs. I will describe ongoing coordination, education and public outreach efforts for the plasma sciences and their interrelation; internet-based web pages (e.g., see plasma homepage) and newsgroup, articles and brochures, educational workshops, exhibits and, among others, a new coalition for all plasma science and technology.

[hTupP3.10] Communicating with Customers.

An important counterpart of our mission as a national laboratory is communicating with customers. These customers include the Department of Energy (DOE), non-DOE entities such as the NASA, Goodyear, and the Department of Agriculture, and the general public. In the Pulsed Power Inertial Confinement Fusion (ICF) Program at Sandia National Laboratories, we provide short (one-page) technical reports to the DOE and to our upper management. Some of these reports are periodic in nature (monthly and quarterly), and some are specifically designed to relay the details of a significant accomplishment. Some are available on our external web site, which is updated monthly. Another major communication each year is the Pulsed Power ICF technical contract with the DOE. A requirement of all these communications is readability, with enough technical detail for the nonspecialist to provide a sense of the purpose, continuity, and progress within the Program. In this poster I will share some of our recent reports and summarize how to communicate effectively with a customer through written materials and the World Wide Web.

[hTupP3.11] Carnegie Science Academy Web Site

The Carnegie Science Academy is a professional society "For Teens...By Teens" at the Carnegie Science Center in Pittsburgh. The CSA Web Site [ http://csa.clpgh.org ] is designed for teens who have an interest in science and technology. This online or virtual science academy provides resources for teens in high school science classes. The Web site also allows students around the world to participate and communicate with other students, discuss current events in science, share opinions, find answers to questions, or make online friends. Visitors can enjoy the main components of the site or sign up for a free membership which allows access to our chat room for monthly meeting, online newsletter, members forum, and much more. Main components to the site include a spot for cool links and downloads, available for any visitor to download or view. Online exhibits are created by students to examine and publish an area of study and also allow teachers to easily post classroom activities as exhibits by submitting pictures and text. Random Access, the interactive part of the academy, allows users to share ideas and opinions. Planet CSA focuses on current events in science and the academy. In the future the CSA Web site will become a major resource for teens and science teachers providing materials that will allow students to further enhance their interest and experiences in science.

[hTupP3.12] The "Fusion EXPO" in Brussels

From the 22nd of october until the 28th of november, a fusion exhibit is being organized in the capital of Europe, Brussels. The aim of the exhibit is threefold : (i) give a feeling for the problem of our future energy supply (ii) show that fusion is possibly one of the most interesting of the very few options we have for our long term energy supply and (iii) to increase public awareness on fusion research. The exhibit deals mainly with magnetic fusion, with some part devoted to inertial fusion. Large photographs of different European fusion devices, maquettes of JET, Tore Supra etc..., parts of existing magnetic fusion experiments (antennas, limiters, etc...) should give the public an idea of what fusion research means in terms of real life. Especially school classes are invited and will be given guided tours of the exhibit. In particular also the members of the European Parliament are invited to the exhibit, and a special symposiom on fusion research will be organized to inform them on the need of this kind of research and the important benefits fusion has to offer over all other known energy sources. The poster will give a visual overview of the exhibit, next to providing some practical experience gathered until then. New materials for public use and especially prepared for this exhibit will be on display.

[hTupP3.13] Plasma Density Measurements in the Large Experiment on Instabilities and Anisotropies

An RF compensated Langmuir probe has been constructed for initial measurements of the plasma density and electron temperature in the Large Experiment on Instabilities and Anisotropies (LEIA) at West Virginia University. LEIA is designed to produce space-relevant plasmas for investigations of collisionless microinstabilities. The Langmuir probe is absolutely calibrated against a microwave reflectometer system. The dependence of the plasma parameters in LEIA on the plasma source RF power, fill pressure, and gas species will be presented. Work supported by the U.S. Department of Energy and the National Science Foundation

[hTupP3.14] Measurement of High-Frequency Waves and Fluctuations in a Dipole-Confined Plasma

In this poster, we report the excitation of high-frequency whistler and lower-hybrid waves launched from a novel magnetostatic antenna located at one of the poles of strong dipole electromagnet. The dipole magnet is used to confine a relatively collisionless plasma populated with energetic electrons. The antenna excites parallel and perpendicular magnetic fluctuations with a dominate azimuthal wave number, m = 3. A broad-band 100 W amplifier drives the antenna at frequencies ranging from 1 to 1000 MHz, and we observe the plasma's response as a function of frequency and radial position. The fluctuations are detected with a small pick-up loop inserted into the plasma at the end of a probe. We plan to interpret the measurements in terms of cold plasma wave theory emphasizing possible focusing and resonances effects due to the strong radial variation of the magnetic field and plasma density.

[hTupP3.15] Measurement of Internally and Externally Excited Electrostatic Wave Structures

In this poster, we report measurements of the radial and angular mode structures of electrostatic fluctuations in a energetic, strongly magnetized plasma confined by a dipole magnetic field. The dipole magnetic field is the most common magnetic field in nature, and it is relatively easy to characterize. We have observed both naturally-occurring and externally excited electrostatic fluctuations. The natural fluctuations have been identified as hot electron interchange instabilities(H.~P.~Warren and M.~E.~Mauel, \textitPhys.~of Plasmas) \textbf2 (1995) 4185. while the driven excitations are created by a newly installed antenna located at one of the poles of the dipole. Several high-impedance, movable floating potential probes are located at various angular positions, and phase-correlations between these probes will allow investigation of the radial and azimuthal wavelengths of the fluctuations.

[hTupP3.16] Measurement of Atmospheric Pressure Arc Jet Velocity

A plasma arc jet originates at the cathode of a DC atmospheric pressure arc due to magnetic pumping(P.M. Bellan. Phys. Rev. Lett. 69, 3515 (1992).). This jet velocity can affect the equilibrium and stability of the arcs in electric arc furnaces used for steel recycling. Previous techniques to measure the arc jet speed included deflection of small pellets(B. Bowman. J. Phys. D: Appl. Phys. 5, 1422 (1972)) and Doppler-shifted plasma scattering(M. Irie et al. J. Phys. D: Appl. Phys. 10, 1599 (1977)). This poster will describe measurements of the arc jet velocity in the 200 Amp PPPL arc furnace, and compare these measurements with arc jet models.

[hTupP3.17] Fast Alfven Wave Interferometry and Reflectometry on the DIII--D Tokamak

A system based on the measurement of the transmission and reflection of the fast Alfven wave in the ion cyclotron range of frequencies can be used to non-perturbatively diagnose the mass density,(H. Ikezi, et al.), Rev.\ Sci.\ Instrum.\ 68, 478 (1997). ion species mixture,(G.L. Greene, Nucl. Fusion 35), 583 (1995). and density fluctuations in a tokamak plasma. Previous proof-of-principle experiments have demonstrated some of these possibilities. In this work, a new system of receiving probes and a dedicated low power (\sim 1~W) antenna have been installed in the DIII--D tokamak to make these measurements during routine tokamak operation. Details of the installation, calibration, and operation of this system will be presented.

[hTupP3.18] NSTX Error Field Calculations

As part of the NSTX design effort good estimates for the probable magnitudes of non-axisymmetric poloidal fields (field errors) are needed. Preliminary calculations indicate that the magnitude of the (2,1) radial component of non-axisymmetric stray field, B^(2,1)_r, should be less than \approx 4.5\ gauss (B_t = 3.0 T) to avoid mode locking. A computer code was written to allow us to produce multiple perturbations in the NSTX poloidal field coil set configuration allowing us to simulate a wide range of ``non-idealness'' in the coil set. The code will be used to quantify the contributions to the non-axisymmetric error field total from various likely sources (e.g., non-coaxial coils, ``out of round'' coils, etc.) of field error. In addition to providing information about the magnitudes of these error fields, these results will be used to help specify a field error correction coil system should it be determined that one will be required as part of the baseline NSTX design. This presentation will outline the capabilities of the computer code and show some results of the ensuing analyses.

[hTupP3.19] Development of a Graphical User Interface to Assess Solutions of 2-D Plasma Transport Equations

Computational methods and modeling provide an important bridge between theory and experiment, especially in plasma physics. A graphical user interface (GUI) has been developed for the edge plasma transport code b2.5.(B.J. Braams, Contrib. Plasma Phys. 36) (1996) 276. Development of this GUI will facilitate more detailed analysis of individual components of the transport equations, as previously it was difficult to obtain anything other than an overall picture of the transport. The GUI allows plotting of densities, velocities, temperatures, and particle heat fluxes, and is designed to be portable. Using this GUI, solutions to the 2-D edge plasma transport equations are assessed with the aim of studying divertor physics. This GUI will be used to study the effect of changing plasma density on the ratio of heat flux flowing to the inboard ond outboard sides of the divertor. Data and simulations will be presented.

[hTupP3.20] Numerical Studies of the Sensitivity of Resistive Wall Mode Feedback Schemes to Sensor Location

A simulation code has been written to analyze the role and sensitivity of the sensor location in resistive wall mode feedback stabilization. The code is based on a RWM formulation which utilizes the concepts of self and mutual inductance to describe the physics of the resistive wall mode. The location and the geometry of the sensor relative to those of the plasma perturbation, the conducting shell, and the active coil directly affect the overall stability of the feedback system. In addition, these same factors influence the systems ability to reject noise which in this case would include signals having an helicity differing from that of the mode we wish to suppress. We will compare results of analyses for both the ``Smart Shell'' and the ``Fake Rotating Shell'' methods of resistive wall mode feedback schemes. This presentation will include results of simulations over a range of machine and operating parameters that encompass the present group of operating tokamaks (US) and possible future experimental devices (e.g., ITER).

[hTupP3.21] Development and Testing of a Chemical Sputtering Model for the Monte Carlo Impurity (MCI) Code

Fluid code calculations indicate that chemical sputtering may be an important process in high density, radiatively detached, tokamak divertor operations. A chemical sputtering model has been designed and installed into the \hboxDIII--D Monte Carlo Impurity (MCI) transport code. We will discuss how the model was constructed and the sources of atomic data used. Comparisons between chemical and physical sputtering yields will be presented for differing plasma conditions. Preliminary comparisons with DIII--D experimental data and a discussion of the benchmarking process will be presented.

[hTupP3.22] Long Mean Free Path Electron Heat Conduction Modifications

Fluid treatments breakdown at surprisingly large collisionality because the energy weighted Coulomb mean free path \lambda is proportional to the square of the energy (\lambda\propto E^2), causing the heat conduction to be dominated by particles with energies on the order of seven times the thermal energy. To investigate modifications of the Spitzer electron heat conductivity we seek self-similar solutions of a high speed expansion of the full electron operator [1]. To simplify further the perpendicular distribution is assumed Maxwellian and integration over perpendicular speeds employed to obtain a collision operator depending only on parallel velocity [2]. Both the physically relevant case \lambda\propto E^2 and the artificial, exactly soluble case \lambda\propto E, are considered. Non-expandable, exponentially small modifications to the parallel heat conduction not retained in conventional short mean free path treatments are shown to be responsible for the departure from Spitzer.

[1] S.~I.~Krasheninnikov, Sov.~Phys.~JETP 67, 2483 (1988).

[2] P.~J.~Catto, J.~R.~Myra, A.~J.~Wootton, Phys.~Plasmas 1, 684 (1994).

*Also Lodestar Research Corporation

**Perm address: Hamilton College, Dept Physics, Clinton, NY

[hTupP3.23] Dimensionless Size Scaling of the H--mode Power Threshold

The scaling of the H--mode power threshold with increasing size is an important topic in tokamak physics. If the increase in the H--mode power threshold is more rapid than the increase in the core transported power (at fixed beta) as the tokamak size is increased, then the H--mode threshold may play a dominant role in the global confinement rather than core transport. Following the scale invariance principle, the relative gyroradius (\rho_*) scaling of the H--mode power threshold has been studied in the DIII--D tokamak while holding the other important dimensionless parameters (beta, collisionality, safety factor, shape, etc.) constant. Utilizing neutral beam injection heating of the plasma, the scaling of the power flow through the plasma edge near the H--mode threshold condition was measured for a factor-of-1.6 scan in \rho_*. This measurement was made for two different values of the collisionality, which altered the power flow in the electron and ion channels and changed the \rho_* scaling of the H--mode threshold power. A two-fluid analysis of the edge transported power will be shown which will examine separately the \rho_* scaling of the electron and ion power flows near the H--mode threshold condition.

[hTupP3.24] Liquid Metal Dynamo Measurements

Detection of convected magnetic fields in a small-scale liquid metal dynamo is attempted. Initial experiments will focus on the conversion of toroidal to poloidal flux (a version of the ømega effect). A precision vector magnetometer will be used to measure the effect of a rotating magnetofluid on a static magnetic field. Water will be used as a control medium and effects will be compared with a conducting medium (liquid sodium or NaK). A small spherical flask (0.16 m diameter) houses 2 liters of fluid, a teflon stirrer creates an asymmetrical flow pattern, and Helmholtz coils generate a constant magnetic field on the order of 10 gauss. The Reynold's number will be of order unity.

[hTupP3.25] Magnetic Reconnection Results on the Swarthmore Spheromak Experiment

Linear and 2D arrays of magnetic probes are used to study magnetic reconnection in the Swarthmore Spheromak Experiment (SSX). Opposing coaxial plasma guns form two identical spheromaks into adjacent 0.5 m diameter copper flux conservers. The flux conservers have symmetrical openings that allow the spheromaks to merge in a controlled manner. The stable equilibrium of the spheromaks provides a reservoir of magnetic flux for reconnection experiments. Currently, the magnetic configuration of the spheromaks allows the study of counter-helicity reconnection. Preliminary analysis will be presented and may include 2D B field movies of the reconnection region, measurement of the reconnection rate and comparison to the Sweet-Parker and standard Petschek models.

[hTupP3.26] Spectroscopic and Particle Diagnostics of SSX Plasmas

SSX spheromaks are generated using two coaxial plasma guns for the purpose of studying magnetic reconnection. Plasmas are studied using a low dispersion optical spectrograph with a CCD camera, three photodiodes through wideband optical filters, an absolute XUV photodiode, a Faraday cup particle detector, and a velocity selector particle detector. Temperatures will be estimated based on particle distribution and spectral analysis. Impurity levels will be estimated from optical spectra. Time resolved particle and photon fluxes will be compared to data from magnetic probes in an attempt to correlate with reconnection events.

[hTupP3.27] A Fast Swept Retarding Field Energy Analyzer for Ion Temperature Measurements in MRX

In the MRX device two plasmas are generated and merged together to produce magnetic reconnection. An integral part of the diagnostic of this process is a RFEA (Retarding Field Energy Analyzer), which measures local ion temperature. The RFEA that was already built consists of two conducting grids and an Mo collector plate. The first grid is negatively biased to repel the electrons. The second, selector grid is positively charged to repel ions of an energy below a particular level. The ions that pass through the second grid are collected on the collector plate. The goal is to measure the collected current versus the bias voltage. However, the present setup enables us to measure only one I vs.V point for each plasma shot. To get the full curve more shots must be fired. This process is quiet inefficient, and it introduces an error since the plasma characteristics can vary from discharge to discharge. To solve this problem a sweeping circuit will be built. This circuit will enable an AC voltage to be passed through the selector grid. A function generator generates a signal that is much faster than the reconnection time in MRX (20 \musec), to assure the proper resolution. An audio amplifier will be used with a transformer which is inside of the sweeping circuit to amplify the AC voltage signal. This will enable us to measure many I vs.V graphs in one plasma shot. Results from the RFEA with the sweeping circuit will be presented.

[hTupP3.28] Plasma Flow Velocity Measurement with a Mach Probe in MRX

Magnetic reconnection refers to the process by which oppositely-directed magnetic fields in plasmas are annihilated, and the subsequent rearrangement of the field lines. Magnetic reconnection plays a central role in the physics of solar flares and of the magnetosphere. In the MRX (Magnetic Reconnection Experiment), the physics of magnetic reconnection is studied in a controlled environment. An important aspect of reconnection phenomena is the plasma flows near the reconnection layer. Measurement of the ion flow velocities will provide a better understanding of the dynamics of reconnection and of the process by which the ions are heated. These measurements can be done with a Mach probe. The probe we use consists of two negatively biased collector plates arranged back-to-back. The difference in the ion saturation current so collected on the two plates yields the net local ion flow velocity. The Mach probe measurements can be compared with the flow velocity assuming ideal MHD obtained from the time evolution measurements of the magnetic flux contours. The results of the plasma flow measurements will be presented and compared with models of the reconnection process.

[hTupP3.29] Effect of Viscosity on MHD Growth Rates in a Wall Confined Z Pinch

Recently there has been renewed interest in the wall-confined Z pinch as a combined magnetic-inertial alternate fusion concept. A critical issue is whether or not sufficient fusion reactions can occur before MHD instabilities destroy plasma confinement. If the unstable modes grow on the ideal MHD time, fusion is not possible. If, however, the modes are significantly slowed down by dissapative and dispersive effects, fusion may be possible. In the present work, the magnetohydrodynamic stability of the Z-pinch configuration is explored numerically, using a one-dimensional eigenvalue code, including viscous effects as described by Braginskii. Realistic radial profiles of the magnetic fields and pressure are used in the studies. The effect of the viscosity terms on the growth rates of instabilities will be presented at the meeting.

[hTupP3.30] Studying the Behavior of Plasma by the use of Microwave Interferometry

Plasma density and transport were studied in a 10 inch diameter hollow cathode discharge using microwave interferometry. The interferometry was a homodyne system operating at 35.14 GHz. Plasma densities of an 10^10~cm^-3 was measured in steady state and their decay monitored in the afterglow. A typical decay time of 0.1 ms was found for argon plasmas at 35 mT.

[hTupP3.31] Suspension of Blood Droplets in an AC Quadrupole at Atmospheric Pressure

Red blood cells are negatively charged electrically to facilitate smooth flow of blood in the mammalian systems. Negative charge helps avoid clumping due to aggregation of cells. Traditionally the charge on the red blood surface has been determined by microelectrophoresis. These measurements are imprecise due to difficulty in determination of many of the constants in Helmholtz-Smoluchowski equation. The charge to mass ratio of human red blood cells can be determined in a quadrupole with more certainty. The mass of the red blood cells was determined by size. Mean corpuscular hemoglobin along with other indices was also determined. The numbers of red and white blood cells were counted by a Coulter counter and microscopy. The blood droplets were injected through a 50 micron orifice into a linear AC quadrupole (Z0 = 6 mm) with a dielectric repeller on axis, driven at 3.69 KV, 60 Hz. The red blood cells separated from whole blood by centrifugation and suspended in a phosphate buffer solution were trapped in the quadrupole. The size of the droplets was determined microscopically to be in between 50-100 microns. We were able to suspend the droplets upto 25 minutes. As the q/m increases due to evaporation of some of the buffer the droplets become unstable and untrapped. We biased the quadrupole with a DC voltage such that top two pole were positive and bottom two negative. By applying the DC voltage we were able to lift the blood droplets showing that the blood droplets were negatively charged. Experiments are in progress to determine an exact number of elementary charges on each red blood cell separated from whole blood.

[hTupP3.32] Isotope Scaling of Tokamak Transport Simulations

The effect of changing hydrogen isotope mass on the temperature and density profiles in tokamak plasmas is investigated using the Multi-Mode Transport Model in time-dependent predictive transport modelling simulations with the BALDUR code. Detailed comparisons are made between the predicted temperature and density profiles and the experimentally measured profiles in TFTR L-mode and supershot plasmas. Particular attention is paid to the effects of plasma impurities, heating profiles, boundary conditions, and neutral atoms coming from the walls of the tokamak. These simulations are carried out using the experimentally measured boundary conditions, sawtooth crash times, and time history of \barn_e and Z_eff for each discharge in a series of systematic isotope scans. In addition, comparison simulations are carried out varying only the hydrogen isotope mass while holding all other conditions fixed.

^*This work supported by US Department of Energy, under contract number DE--FG02--92--ER--54141 and by NSF--REU PHY--9322015.

[hTupP3.33] Measurement of Barium Densities in an RF Discharge

The barium atom possesses a number of characteristics that indicate Barium glow discharges may provide the basis for a high-efficiency (possibly with good color-rendering index) lighting technology. The excitation energy of the primary radiating level is less than half the ionization energy. The wavelength of the resonance transition at 553nm is very close to the maximum sensitivity of the human eye. Adequate vapor pressures of Barium can only be achieved at elevated, but accessible, temperatures (5 mTorr at 585^\circC). We are using optical absorption to study the Ba atom density in a low-pressure inductively-coupled plasma in which the Ba vapor pressure is maintained by the discharge itself. Progress on measuring the Ba density as a function of the rf input power will be reported.

[hTupP3.34] Scaling of Zeff in TFTR discharges

In a power-producing tokamak fusion reactor the central Zeff will need to be close to 1 to avoid excessive dilution of the deuterium and tritium fuel, and loss of energy via radiation. Typical values for Zeff in present tokamak experiments are often around 2 or higher. A scaling relation has been derived for Zeff for a variety of tokamaks, in terms of the total radiation power, the surface area of the last closed flux surface, the line-averaged electron density, and the Z of the intrinsic impurity [G.F. Matthews, et al., J. Nucl. Materials, 241-243, p. 450]. We derive similar scaling relations for TFTR discharges with a large variety of regimes and wall preparation techniques. The regimes include Ohmic, supershots, L-mode, reverse shear, and discharges with seed gas impurity injection to cause large radiation fractions. The wall preparation techniques include borinization and various schemes for injecting lithium into the plasma edge.

Part h of program listing