Auroral electron acceleration by dissipative solitary kinetic Alfven waves

The acceleration of auroral electrons has long been an open problem. In a recent work [Wu, Phys. Plasmas 10, 1364 (2003)], the model of a dissipative solitary kinetic Alfven wave (DSKAW) has been proposed to describe the physics of strong electric spikes observed often in the auroral ionosphere and magnetosphere. In this Brief Communication, the DSKAW model is applied to the auroral acceleration region and the possibility of DSKAWs producing auroral electrons is further discussed. The result shows that DSKAWs in the acceleration region can accelerate electrons enough to reach auroral energies and that the most efficient acceleration occurs just at the bottom of the acceleration region where the Alfven speed also peaks. Moreover, the acceleration mechanism by DSKAWs can plausibly explain the cut-off above 10 keV, which is inferred from the energy distribution of auroral precipitating electrons. (C) 2003 American Institute of Physics.