THE WORK WILL COMPLETE THE PROJECT UNDERSTANDING ION HEATING AND CONVECTION USING TWINS AND SWMF ORIGINALLY STARTED AT WEST VIRGINIA UNIVERSITY. THE PRIMARY GOAL OF THIS PROPOSAL IS TO DETERMINE MECHANISMS OF ION HEATING IN THE NEAR.EARTH PLASMA SHEET DURING DIFFERENT DRIVING CONDITIONS AND UNDERSTAND HOW THEY AFFECT INNER MAGNETOSPHERE DYNAMICS. THE OBJECTIVES OF THE PROPOSED PROJECT ARE TO ADDRESS THE FOLLOWING SCIENCE QUESTIONS: OBJECTIVE 1: DOES THE DOMINANT ION HEATING MECHANISM VARY FOR DIFFERENT DRIVING CONDITIONS? USING DATA.MODEL COMPARISONS WE WILL STUDY THE PHYSICAL PROCESSES THAT EXPLAIN THE OBSERVED ION TEMPERATURES CALCULATED FROM ENERGETIC NEUTRAL ATOM MEASUREMENTS DURING DIFFERENT IMF AND STORM CONDITIONS. OBJECTIVE 2: HOW DOES THE CHANGE IN ION TEMPERATURES AFFECT THE ION DRIFT PATHS FOR DIFFERENT DRIVING CONDITIONS? ION DRIFT PATHS DETERMINE THE EFFECTIVENESS OF A STORM THUS WE WILL USE DATA.MODEL COMPARISONS TO RESOLVE THE COMPLEX ROLES THAT ION TEMPERATURES AND DRIVING CONDITIONS PLAY IN THE ION DRIFT DYNAMICS. OBJECTIVE 3: WHAT ROLE DOES THE NEUTRAL DYNAMICS PLAY IN ALTERING THE ION TEMPERATURES DURING DIFFERENT DRIVING CONDITIONS? THE NEUTRAL GEOCORONA PLAYS A KEY ROLE IN THE CREATION OF ENAS AND THE DEPLETION OF THE RING CURRENT. DATA.MODEL COMPARISONS WILL BE USED TO IMPROVE OUR UNDERSTANDING OF THE INFLUENCE OF DRIVING CONDITIONS ON THE GEOCORONAL DENSITY.