Interaction of Alfvén front with the plasma anomalous resistance layer

Abstract.The efficiency of the Alfvén impulse excitation in the auroral zone of the terrestrial magnetosphere upon the onset of the anomalous field-aligned resistance has been estimated. The impulsive disturbance excited during the onset of anomalous field-aligned resistance and electric field may signify the transition of a global magnetospheric instability into the explosive phase with positive feedback. We consider the self-consistent problem on excitation of anomalous resistance at the front of field-aligned current and reverse influence upon it from the induced currents. The analytical solution of the self-consistent problem has shown that during the entrance of field-aligned current front into the anomalous resistivity layer (ARL) an Alfvénic impulse is generated. The interaction of the external current with ARL results in the delay of the current growth. The impulse duration and delay time depend on the ratio between the Alfvén damping scale and external current width. The solution obtained indicates the possibility of using the Alfvénic impulse as an indicator of distant occurrence of anomalous resistance.