Improvements in the implicit simulation of plasmas

Summary form only given. The ANTHEM code uses the implicit moment method to calculate plasma dynamics over time steps far exceeding the local plasma period and spatial scales well beyond a Debye length. Numerous improvements have been implemented since the first description of the code. It has been found that nonlinear magnetic waves may require an implicit treatment of the ν×B term in the auxiliary moment equations used in the implicit field solution. Such waves are associated with deep magnetic field penetration of opening switch plasmas. It has been noted that a differencing that stores electric field components both normal and parallel to cell faces is needed to minimize numerical diffusion of the magnetic field. It was found that ghost cells in conductors must be given a very high fictitious density to force the proper boundary values in the implicit solutions for these electric field components, thereby avoiding erroneous electron emission. It was also found that a cell-local time step must be used with implicit full-particle modeling to avoid finite grid instability heating