ON HIGH-LATITUDE CONVECTION FIELD INHOMOGENEITIES, BIRKELAND CURRENTS AND INVERTED 'V' PRECIPITATION EVENTS

摘要

Basic principles of particle acceleration by means of electrostatic potential gradients along the geomagnetic field are discussed with emphasis on curl-free electric field configurations compatible with observed high latitude convection field reversals and inverted V precipitation events. The potential drop along the magnetic field lines was assumed to arise from some (non-specified) kind of anomalous resistivity that is induced by sufficiently intensified Birkeland currents. The inverted V shaped profile of energy versus latitude, frequently observed at the 9precipitation events, was found consistent with a convection profile known to occur in the low magnetosphere at high magnetic latitudes. The combined effect of the anomalous resistivity and the locally enhanced ionization due to precipitation was seen to imply a strong reduction of the convection field within an associated auroral structure. A plausible mechanism that may contact upward flowing Birkeland currents, preceding the formation of anomalous resistivity, is also discussed. (Author)