Dissipative solitary kinetic Alfvén wave and electron acceleration

Some recent studies of observations in situ by space satellites show that low frequency electromagnetic fluctuations in the auroral ionosphere and magnetosphere can often be identified as soliatry kinetic Alfvén waves (SKAWs), and further analyses of the data reveal clearly that electron collisional dissipation can considerably affect the structure and evolution of SKAWs. In this paper, a model of nonlinear kinetic Alfvén waves, called a dissipative SKAW (DSKAW), is presented, in which the effect of electron collisional dissipation has been taken into account. The results show that DSKAW can produce a local shock-like structure with a net parallel electric potential drop, in which the associated parallel electric field is primarily caused by nonlinear electron inertia. In particular, it is argued that DSKAW can accelerate electrons efficiently to the order of the local Alfvén velocity. This suggests that DSKAW can provide an efficient acceleration mechanism for energetic electrons, which can frequently be encountered in various space and cosmic plasma environments.