PC spectra analysis of L-shell copper X-pinch plasma produced by the compact generator of Ecole polytechnique

Abstract

Principal Component Analysis (PCA) is applied and compared with the line ratios of special Ne-like transitions for investigating the electron beam effects on the L-shell Cu synthetic spectra. The Principal Components (PC) of L-shell Cu are extracted over a non-LTE collisional radiative L-shell Cu model with and without presence of hot electrons to discuss the electron beam effects. Furthermore, PC spectra of Ne-like transitions are also studied as an alternative diagnostics to investigate the polarization sensitivity of these transtions. The extracted PCs are used to estimate the plasma electron temperature, density and beam fractions from a representative time-integrated spatially-resolved L-shell Cu X-pinch plasma spectrum. The experimental spectrum is produced by the explosion of 25-µm Cu wires on a compact L-C (40 kV, 200 kA, 200 ns) generator. The modeled plasma electron temperatures are about Te ∼ 125eV and ne = 5×1019 cm−3 in the presence of the fraction of the beams with f ∼ 0.05 and centered energy of ∼10 keV.