Short Pulse Laser Absorption and Energy Partition at Relativistic Laser Intensities

Shepherd, R ; Chen, H ; Ping, Y ; Dyer, G ; Wilks, S ; Chung, H ; Kemp, A ; Hanson, S ; Widmann, K ; Fournier, K ; Faenov, A ; Pikuz, T ; Niles, A ; Beiersdorfer, P

Lawrence Livermore National Laboratory

关键词: Comets;    Electrons;    Absorption;    70 Plasma Physics And Fusion;    Simulation;   

DOI  :  10.2172/908084
RP-ID  :  UCRL-TR-229579
RP-ID  :  W-7405-ENG-48
RP-ID  :  908084

美国|英语

来源: UNT Digital Library

【 摘 要 】

We have performed experiments at the COMET and Calisto short pulse laser facilities to make the first comprehensive measurements of the laser absorption and energy partition in solid targets heated with an ultrashort laser pulse focused to relativistic laser intensities (>10 10{sup 17} W/cm{sup 2}). The measurements show an exceedingly high absorption for P polarized laser-target interactions above 10{sup 19} W/cm{sup 2}. Additionally, the hot electron population is observed to markedly increase at the same intensity range. An investigation of the relaxation process was initiated u using time sing time-resolved K{sub {alpha}} spectroscopy. Measurements of the time time-resolved K{sub {alpha}} radiation suggest a 10-20 ps relativistic electron relaxation time. However modeling difficulties of these data are apparent and a more detailed investigation on this subject matter is warranted.