Publications Details

Evidence of non-Maxwellian ion velocity distributions in spherical shock-driven implosions

Mannion, Owen M.; Taitano, W.T.; Appelbe, B.D.; Crilly, A.J.; Forrest, C.J.; Glebov, V.Y.; Knauer, J.P.; Mckenty, P.W.; Mohamed, Z.L.; Stoeckl, C.; Keenan, B.D.; Chittenden, J.P.; Adrian, P.; Kabadi, N.; Frenje, J.; Gatu Johnson, M.; Regan, S.P.

The ion velocity distribution functions of thermonuclear plasmas generated by spherical laser direct drive implosions are studied using deuterium-tritium (DT) and deuterium-deuterium (DD) fusion neutron energy spectrum measurements. A hydrodynamic Maxwellian plasma model accurately describes measurements made from lower temperature (<10 keV), hydrodynamiclike plasmas, but is insufficient to describe measurements made from higher temperature more kineticlike plasmas. The high temperature measurements are more consistent with Vlasov-Fokker-Planck (VFP) simulation results which predict the presence of a bimodal plasma ion velocity distribution near peak neutron production. These measurements provide direct experimental evidence of non-Maxwellian ion velocity distributions in spherical shock driven implosions and provide useful data for benchmarking kinetic VFP simulations.