Coupled MHD-Monte Carlo transport model for dense plasmas

Abstract

A two-dimensional, two fluid model of the MHD equations has been coupled to a Monte Carlo transport model of high energy, non-Maxwellian ions. The MHD part of the model assumes complete ionization and includes a perfect gas law for a scalar pressure, a tensor artificial viscosity, electron and ion thermal conduction, electron-ion coupling, and a radiation loss term. A simple Ohm's Law is used with a Bθ magnetic field. The MHD equations were solved in Lagrangian coordinates. The conservation equations were differenced explicitly and the diffusion-type equations implicitly using the splitting technique. The Monte Carlo model solves the equation of motion for high energy ions, moving through and suffering small and large angle collisions with the fluid Maxwellian plasma. The source of high energy ions is the thermonuclear reactions of the hydrogen isotopes, or it may be an externally injected beam of neutralized ions. In addition to using the usual Maxwell averaged thermonuclear cross sections for calculating the number of reactions taking place within the Maxwellian plasma, the high energy ions may suffer collisions resulting in a reaction. In the Monte Carlo model all neutrons are assumed to escape, and all energetic ions of Z less than or equal to 2 are followed.