The acceleration of energetic electrons has long been one of the most outstanding problems in astrophysics and space physics, and some recent observations from space satellites show that low-frequency electromagnetic fluctuations in the auroral ionosphere and magnetosphere can often be identified as the kinetic Alfven modes. A model of nonlinear kinetic Alfven waves is presented here, in which the effect of electron collisional dissipation has been taken into account. The result is a dissipative solitary kinetic Alfven wave (DSKAW), which can produce a local shocklike structure with a net electric potential drop and which can thereby accelerate efficiently the electrons to the order of the local Alfven velocity. Since Alfvenic fluctuation is the most common electromagnetic activity in extensive cosmic plasma environments, the present result suggests that the DSKAW could play an important role in the acceleration and energization of cosmic plasmas.
机构:
Space Res Inst, 84-32 Profsoyuznaya Str, Moscow 117997, Russia
IZMIRAN, Troitsk 142190, RussiaUPMC Univ Paris 06, Univ Paris Saclay, PSL Res Univ,Ecole Polytech, Univ Paris Sud,Observ Paris,Sorbonne Univ,LPP,CNR, F-91128 Palaiseau, France