Session GP1 - Poster Session IV.
POSTER session, Tuesday afternoon, October 30
Exhibit Hall B,
Coaxial gun-injected power provides buildup and sustainment in SSPX. Current flowing along the open field lines in the spheromak edge dissipates power in electrode sheaths, the resistive edge, and coupling to plasma turbulence. In this paper we compare both power and helicity balance models to calculate plasma buildup. Because both power and helicity are rapidly dissipated in the sheaths and edge resistance, the power and helicity input providing for buildup is modeled from the observed increase in gun impedance above a current threshold. Measurements of the gun voltage and current provide information on the gun impedance. From Thomson scattering measurements of the electron temperature and the CORSICA mhd equilibrium, estimates can be made for the edge dissipation and \etaJ^2 resistive losses within the spheromak core. This work was performed under the auspices of US DOE by the University of California Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48.