X-ray beams produced by hot electrons with directional drift velocity in fusion plasmas

Spectra and emission efficiencies of x-rays produced by hot electrons (hot-e's) with drift Maxwellian distribution are studied using both analytical and numerical methods. The analytic expressions are particularly useful for the analysis of x-ray spectra produced by hot-e's in laser-produced plasma. Both analytical and numerical results show that when hot-e's have a nonzero drift velocity, the bremsstrahlung spectrum is still approximately a linear function in logarithmic coordinates, which indicates that the process of inferring hot-e's temperature from the slope of x-ray spectrum needs to be revisited under certain circumstances.