MEASUREMENTS OF SUPRATHERMAL ELECTRONS IN HOHLRAUM PLASMAS WITH X-RAYSPECTROSCOPY

Nonthermal excitation of atomic states by suprathermal electrons was o bserved for the first time within inertial confinement fusion hohlraum plasmas. The nonthermal excitation process results in the simultaneou s emission of the Ly-alpha transition and the K-shell satellite series (lithiumlike through carbonlike) which were observed on temporally re solved x-ray emission spectra. A quantitative analysis with a time-dep endent collisional-radiative non-Maxwellian model shows that these spe ctra can be used to obtain temporally and spatially resolved measureme nts of the suprathermal electron fraction in indirectly driven inertia l confinement fusion targets.