Alfven solitons in a Fermionic quantum plasma

The propagation of Alfven envelope solitons through a Fermionic quantum plasma is considered. Starting from the governing equations for Hall magnetohydrodynamics including quantum corrections, coupled Zakharov-type equations are derived for circularly polarized Alfven waves. The equations are numerically solved for time-independent and time-dependent cases. The time-independent case shows that variations in density take the form of dressed density solitons in which an approximately Gaussian peak is surrounded by smaller sinusoidal variations in the density envelope. The mathematical basis for this behavior is explained. A limited time-dependent case is obtained which uses the numerical time-independent soliton solutions as the initial conditions. This confirms that the soliton solutions retain the same profile as they propagate. The relevance of this work to dense astrophysical plasmas like the interiors of white dwarf stars is discussed.