Computational study of hot electron generation and energy transport in intense laser produced hot dense matter
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Present ultra high power lasers are capable of producing high energy density (HED) plasmas, in controlled way, with a density greater than solid density and at a high temperature of keV (1 keV ~ 11,000,0000 K). Matter in such extreme states is par- ticularly interesting for (HED) physics such as laboratory studies of planetary and stellar astrophysics, laser fusion research, pulsed neutron source etc. To date however, the physics in HED plasma, especially, the energy transport, which is crucial to re- alize applications, has not been understood well. Intense laser produced plasmas are complex systems involving two widely distinct temperature distributions and are dif- ficult to model by a single approach. Both kinetic and collisional process are equally important to understand an entire process of laser-solid interaction. By implement- ing atomic physics models, such as collision, ionization, and radiation damping, self consistently, in state-of-the-art particle-in-cell code (PICLS) has enabled to explore the physics involved in the HED plasma.Laser absorption, hot electron transport, and isochoric heating physics in laser produced hot dense plasmas are studied with the help of PICLS simulations. In particular, a novel mode of electron acceleration, namely DC-ponderomotive acceler- ation, is identified in the super intense laser regime which plays an important role in the coupling of laser energy to a dense plasma. Geometrical effects on hot elec- tron transport and target heating processes are examined in the reduced mass target experiments. Further, pertinent to fast ignition, laser accelerated fast electron diver- gence and transport in the experiments using warm dense matter (low temperature plasma) is characterized and explained.