Thomson Scattering Measurements of Temperature and Density in a Low-Density, Laser-Driven Magnetized Plasma

Abstract

We present electron temperature and density measurements from Thomson scattering on recent collisionless shock experiments on the Trident laser at Los Alamos National Laboratory. A graphite target placed inside a static magnetic field (≲1 kG) created by a 50 cm-diameter Helmholtz coil was ablated by a 1053 nm beam, which created a low-density, magnetized plasma. A separate 527 nm beam was used for Thomson scattering to characterize the plasma 3 cm radially from the target and 0.5-8.5 μs after ablation. The electron temperature was found to be relatively constant over 8 μs at 11-13 eV and, combined with Rayleigh scattering, the electron density was found to be 2 × 1014−4 × 1014 cm−3 over the same timescale. Several carbon emission lines were also observed in the Thomson spectrum and were utilized to independently measure the electron temperature and density and to characterize the plasma charge state.