Enhanced heat transport in ablation plasma under transverse magnetic field by upper hybrid resonance heating

Abstract

Heat transport properties in a kilotesla transverse magnetic field are compared for the two propagation modes, so-called ordinary (O) and extraordinary (X) modes, of laser using one-dimensional collisional particle-in-cell simulations with ablation-plasma-like settings. The evanescent wave of the X-mode laser is expected to cause an upper hybrid resonance from its dispersion relation, as opposed to the O-mode. Our simulations revealed that significantly hot electrons can be generated by the resonance even if the evanescent wave is initially unreachable to the resonance position, because the radiation pressure steepens the density profile and shortens the cutoff-to-resonance distance. The hot electrons are found to produce a significant amount of heat flux while keeping the transport by the bulk electrons, which results in an enhanced total heat transport.