Time-resolved temperature measurement of a pinched plasma using the dispersive x-ray analysis of the continuum emission

Abstract

The dispersive analysis of the x-ray continuum is employed to determine the electron temperature of a dense pinched plasma. A curved crystal spectrometer was used to obtain the desired dispersion, and two or more p-i-n (doubly diffused silicon) diodes were used to monitor the time-resolved emission. The dispersive technique is inherently more accurate than filtering techniques and simpler to implement than laser scattering techniques. In an experimental verification of the technique, the time-resolved temperature of a plasma focus pinch was measured under various conditions, and was found to be consistent with density observations and MHD calculations. It was possible to observe the cooling effect of radiation emission from seeded plasma focus discharges. The elliptical crystal spectrometer is shown to be well suited to the analysis of the x-ray emission from a pinched plasma source.

BBO-crystal optical parametric oscillator tunable over the 300 — 2340 nm range and pumped by the 4th harmonic of a Nd:YAG laser

“…Additional x-ray diagnostics are also being developed to further understand the plasma behavior. A curved crystal x-ray spectrometer will be deployed to eliminate the spectral ambiguities of the Ross filter x-ray diode detectors and provide information about the importance of impurity lines (Venneri, 1990b). This diagnostic will be particularly valuable in the event that doped deuterium fibers are studied.…”