Pic Modeling of Omega Experiments on Ablation of Plasmas

The charge separation and large electric fields generated by a laser pulse propagating in an under-dense plasma can accelerate the electrons to very high energies. The hydrodynamic model cannot longer describe the evolution of groups of hot electrons of different energy ranges and kinetic particle-in-cell (PIC) simulations are required. The Smilei PIC code is used to investigate the generation and fraction of hot electrons in under-dense plasmas produced by laser pulses in the Omega experiments [1] . In 2D PIC simulation using Smilei, a square-shaped laser pulse with the intensity of 10 15 W/cm 2 and wavelength of 351 nm enters into an initially undisturbed under-dense plasma. The space and time evolution of a fraction of hot electrons in a plasma is investigated. The evolution of number density, velocity, and energy spectra of electrons is studied. The total ion, electron, and electromagnetic field energies of a plasma as a function of time are evaluated. These PIC results provide insights into the contribution and importance of the kinetic effects in the expansion dynamics of ablated plasmas, thereby helping to analyze and explain the Omega experimental data and computational fluid dynamics results.