Form of the continuous x-ray spectrum of a laser plasma

Abstract

A calculation is made of the form and intensity of continuous x-ray emission by a laser plasma in the range ω = 4–40 keV. The spectrum is calculated using a hydrodynamic model of the laser corona and taking into account the ionization kinetics. It is assumed that the electron thermal conductivity has an anomalously low value in the vicinity of the critical point. The x-ray spectrum is of the two-temperature nature due to a strong spatial inhomogeneity of the electron temperature. The high-temperature part of the spectrum (ω > 8 keV) is due to a thin plasma layer (thickness amounting to a few microns) adjoining the outer side of a hydrodynamic deflagration discontinuity (rarefaction jump) on the critical surface.