ENERGY-TRANSFER BETWEEN THE SOLAR-WIND AND THE MAGNETOSPHERE-IONOSPHERE SYSTEM

The coupling of energy between the solar wind and the magnetosphere ha s been studied using many different techniques. Early research used si mple statistical methods and cross-correlation analyses. Such work sug gested that solar wind-magnetosphere coupling is strongly controlled b y the interplanetary electric field (-V x B). Later studies have used more sophisticated techniques such as linear prediction filtering to u nderstand quantitatively the time scales and efficiency of such coupli ng. In fact, there emerge two distinct aspects and time scales for cou pling processes: (1) Directly-driven ionospheric dissipation with resp onse time scales of 10-20 min.; and (2) Storage-release mechanisms inv olving energy loading in the magnetotail for similar to 1 hour. Very r ecent research has used nonlinear dynamical models and nonlinear filte r techniques to incorporate both directly driven and loading-unloading behavior. The result is that very accurate predictions of magnetosphe re-ionosphere response are possible using state-input space reconstruc tion and ''nearest neighbor'' nonlinear filters.