Ionospheric energy input as a function of solar wind parameters: global MHD simulation results

M. Palmroth, P. Janhunen, T. I. Pulkkinen, H. E. J. Koskinen
2004 Annales Geophysicae  
We examine the global energetics the solar wind magnetosphere ionosphere system by using the global MHD simulation code GUMICS-4. We show simulation results for a major magnetospheric storm (April 6, 2000) and a moderate substorm (August 15, 2001). The ionospheric dissipation is investigated by determining the Joule heating and precipitation powers in the simulation during the two events. The ionospheric dissipation is concentrated largely on the dayside cusp region during the main phase of the
more » ... e main phase of the storm period, whereas the nightside oval dominates the ionospheric dissipation during the substorm event. The temporal variations of the precipitation power during the two events are shown to correlate well with commonly used AEbased proxy of the precipitation power. The temporal variation of the Joule heating power during the substorm event is well-correlated with a commonly used AE-based empirical proxy, whereas during the storm period the simulated Joule heating is different from the empirical proxy. Finally, we present a power law formula, which gives the total ionospheric dissipation from the solar wind density, velocity and magnetic field z-component and which agrees with the simulation result with more than 80% correlation. Correspondence to: M. Palmroth
doi:10.5194/angeo-22-549-2004 fatcat:m4zmycp2qfc73cfoeqayjjram4