X-ray spectral measurement of high-temperature plasma parameters in porous targets irradiated with high-power laser pulses

The X-ray spectra of multiply charged ions were recorded from planar agar (C₁₂H₁₈O₉)_n based targets with an average density of 2 mg cm^-3 irradiated by high-power laser pulses (λ = 1.054 μm, τ = 2.5 ns, I ≈ 5 ×10¹³ W cm^-2). The spectra were recorded with a high spectral and spatial resolution employing spherically bent (focusing) crystals of mica and quartz. An analysis of the experimental data obtained by the irradiation of Al₂O₃-doped agar samples allowed us to determine the main parameters of the plasma produced inside the targets. The ion temperature of plasma in low-density porous targets was estimated for the first time to be 1.5 – 2 times higher than the electron temperature.