X-ray emission spectrum of a magnesium plasma heated by picosecond ruby laser pulses

An investigation was made of the x-ray emission spectrum of a magnesium plasma heated by ruby laser pulses of 10–20 psec duration and 10¹⁴ W/cm² power density on the target surface. The relative intensities of the spectral lines were used to determine the electron temperature (200 eV), density [(1–1.15) × 10²⁰ cm^–3], and ionization state ([Li]/[He] ≈ 1) of the luminous part of the plasma. The relative intensities of the resonance lines of the H- and He-like ions yielded an estimate of the electron temperature in the vicinity of the critical point (T_cr550–700 keV).