Temperature mapping of compressed fusion pellets obtained by monochromatic imaging

We report the first use of toroidally bent crystals to record two-dimensional, spatially resolved, monochromatic images of laser-produced fusion plasma. The electron temperature was determined by seeding the deuterium fuel with argon and evaluating the intensity ratio of the two monochromatic images in the Ar+ 17Ly β and the Ar+ 16He β lines. Silicon and germanium crystals were chosen to achieve high diffraction reflectivities. Spatial resolution better than 10 μm was achieved by bending the crystals toroidally to minimize the geometrical aberrations [E. Förster, K. Gäbel, and I. Uschmann, Laser Particle Beams 9, 135 (1991)]. Comparison of the two line intensities requires a calibrated imaging system. Monochromatic images of fusion pellets driven with the GEKKO XII glass laser system are presented.