Temperature Diagnostics for Field-Reversed Configuration Plasmas on the Pulsed High Density (PHD) Experiment

Abstract

The high flux source for the Pulsed High Density Experiment (PHDX) has been constructed, and field-reversed configuration (FRC) plasmas are being produced. To diagnose FRC plasma temperatures three kinds of diagnostic systems have been set up on PHDX; λ = 632.8 nm He-Ne laser interferometer system at the midplane for total temperature T_total, 16 channel spectrometer for ion temperature T_i and soft x-ray (SXR) measurement system for electron temperature T_e viewed along z-axis, respectively. The SXR measurement system consists of five sets of collimators and AXUV100 photodiodes with directly deposited filters which have different bandpass regions. As a result of preliminary temperature diagnostics, the following plasma parameters are estimated during a relatively quiescent phase of FRCs; T_total ∼ 50 eV, T_i ∼ 50 eV and T_e ∼ 25 eV. This result does not agree with the equilibrium relation of T_total ≈ T_i + T_e, and it must be caused by plasma condition and our assumptions in the spectral analysis.