Nonlinear wave interaction and spin models in the magnetohydrodynamic regime

作者：Brodin G^*; Lundin J; Zamanian J; Stefan M

来源：New Journal of Physics, 2011, 13: 083017.

DOI：10.1088/1367-2630/13/8/083017

Here we consider the influence on the electron spin in the magnetohydrodynamic (MHD) regime. Recently developed models that include spin-velocity correlations are taken as the starting point. A theoretical argument is presented, suggesting that in the MHD regime a single-fluid electron model with spin correlations is equivalent to a model with spin-up and spin-down electrons constituting different fluids, but where the spin-velocity correlations are omitted. Three-wave interaction of two shear Alfven waves and a compressional Alfven wave is then taken as a model problem to evaluate the asserted equivalence. The theoretical argument turns out to be supported, because the predictions of the two models agree completely. Furthermore, the three-wave coupling coefficients obey the Manley-Rowe relations, which further support the soundness of the models and the validity of the assumptions made in the derivation. Finally, we point out that the proposed two-fluid model can be incorporated in standard particle-in-cell schemes with only minor modifications.

• 出版日期2011-8-12