Kinetic Alfven solitons in a low-beta plasma under the influence of electron drift motion

Fully nonlinear kinetic Alfven solitary waves are investigated, taking account of the drifting effect of electrons in the direction of the external magnetic field in a low-beta plasma (where beta = 8 pi n(0)T/c(2)B(0)(2) is the ratio of the kinetic pressure to the magnetic pressure). Both compressive and rarefactive Alfven solitons are found to exist in different ranges of k(z) (direction of wave propagation), depending on the values of M (the Mach number) and v'(e) (the drift velocity, occurring implicitly in an effective parameter A). The existence domain of kinetic Alfven solitons is found to be concentrated in the upper regime of beta (much less than 1) and lower regime of M (< 1), but the values of M in the case of rarefactive solitons are observed to be higher than those of compressive solitons. The range of existence of kinetic Alfven solitons is substantially narrowed when the initial drift velocity v'(e) of the electrons is taken into account.