Generation of Alfvén waves in an anomalous resistivity region

Abstract

We have considered disturbances produced by a field-aligned current flowing through a thin layer with a finite conductivity along the magnetic field. The layer conductivity is an arbitrary function of transverse coordinates and time. It is shown that a suddenly emerging layer of the anomalous resistivity in the region of the auroral field-aligned currents leads to a generation of an Alfvén impulse with an amplitude up to 100 gammas. All electromagnetic disturbances appear to be localized inside the magnetic field tube passing through the anomalous resistivity region. An attempt to hinder the field-aligned current with an insulator does not stop the current, but forces it to flow round the insulator.