Figure 4. Theoretical spectra modelling by ATOMIC code.

(a) Modelling was provided in assumption of plasma X-ray emission radiation from 3 plasma Zones (see Fig. 1). For all Zones 6 μm target thickness was used; Zone 1: T_e = 320 eV, N_e = 2 × 10²³ cm⁻³; Zone 2: T_e = 55 eV, N_e = 3 × 10²³ cm⁻³; Zone 3: T_e = 5 eV, N_e = 3 × 10²³ cm⁻³. Intensity in Zone 2 was divided to factor 0.7 × 10³, intensity in Zone 3 was divided to factor 1.1 × 10⁴; Zones 2 and 3 do not include self-opacity effects but do include 1% hot electrons and a Planckian X-ray pump source with T_r = 1.5 keV, which is enhanced in Zone 3 by a factor of 10. The measured spectral regions registered by the second and third order reflections of the mica-crystal spectrometer are indicated in gray; (b) Comparison of theoretical and measured spectra, from 6.8 J laser pulse incident on 6 μm Al foil. The proportions of radiation input from the all 3 plasma Zones were adjusted to match the experimental spectrum, and suggest that the Zone 1 emission persists much longer than the emission from Zones 2 and 3.