The Harang discontinuity and magnetospheric forecasting

This paper describes the physics of the Harang discontinuity and its application to forecasting of the magnetospheric environment. Gradient/curvature depletion of energetic ions from earthward drifting flux tubes results in upward Birkeland currents. Ionospheric closure rotates the dawn-dusk convection electric field resulting in the Harang reversal. This physical mechanism has been incorporated into the Rice Convection Model (RCM) and can serve as a fundamental part of the forecasting of the magnetospheric system. The inclusion of this physics within the RCM results in a physical picture of the Harang discontinuity which did not previously exist. Model results are close to observations and represent a significant improvement in predicted electric field and Birkeland current patterns.