THIS EFFORT WILL INVESTIGATE THE EFFECT OF SPATIAL AND TEMPORAL VARIATIONS IN THE CHORUS-DRIVEN ENERGY AND PITCH ANGLE DIFFUSION OF TRAPPED INNER MAGNETOSPHERIC PARTICLES ON THE EVOLUTION OF THE RING CURRENT AND RADIATION BELTS (RB). PREVIOUS EFFORTS TO MAP THE GLOBAL DISTRIBUTION OF CHORUS WAVES IN THE MAGNETOSPHERE HAVE RELIED ON HEAVILY-AVERAGED OBSERVATIONS TAKEN OVER LONG PERIODS OF TIME TYPICALLY CHARACTERIZED IN TERMS OF GLOBAL GEOMAGNETIC INDICES. THESE AVERAGE MAPS OF WAVE ACTIVITY ARE THEN USED TO DEVELOP DRIFT-AVERAGED MODELS OF PITCH ANGLE AND ENERGY DIFFUSION WHICH MAY BE USED IN MODELS OF RB EVOLUTION. WHILE SUCH STUDIES ARE USEFUL IN BROADLY DESCRIBING THE EFFECTS OF CHORUS WAVES ON THE ENERGY AND PITCH ANGLE EVOLUTION OF THE RB AND RING CURRENT THE VAST RANGE OF VARIATIONS BETWEEN INDIVIDUAL STORMS LIMIT THEIR USE IN UNDERSTANDING THE IMPORTANT PHYSICAL PROCESSES THAT SHAPE THE DIFFERENT OUTCOMES OF PARTICULAR GEOMAGNETIC EVENTS. RECENT WORK HAS FOUND THAT EVENT-SPECIFIC VALUES OF CHORUS WAVE PROPERTIES ARE CRITICAL TO ACCURATELY REPRODUCE RB DYNAMICS. CLEARLY THESE DYNAMICS DEPEND HEAVILY ON CHORUS-DRIVEN ENERGY AND PITCH ANGLE DIFFUSION YET THERE IS NOT A QUANTITATIVE UNDERSTANDING OF THE VARIATIONS IN WAVE PROPERTIES THAT ARISE DURING VARIOUS STORM PHASES OR SOLAR WIND DRIVING AND HOW THOSE REALISTICALLY SCALE THE DIFFUSION COEFFICIENTS. SCIENCE QUESTIONS: (1) WHAT IS THE RANGE OF VARIATION IN OCCURRENCE AND AMPLITUDES OF CHORUS WAVES BETWEEN STORMS AND HOW DO THESE DIFFER FROM MAPS OF THE AVERAGE CHORUS WAVE ACTIVITY? (2) WHAT IS THE IMPACT OF SPATIAL AND TEMPORAL VARIATIONS IN CHORUS WAVE ACTIVITY ON TRAPPED PARTICLE POPULATIONS? (3) HOW DOES THE DISTRIBUTION OF WAVES VARY DURING STORMS DRIVEN BY CORONAL MASS EJECTIONS (CMES) IN CONTRAST TO THOSE DRIVEN BY HIGH SPEED SOLAR WIND STREAMS (HSSWS)? (4) ARE THE DIFFUSIVE EFFECTS OF CHORUS WAVES SUFFICIENT TO EXPLAIN OBSERVED LOCAL ACCELERATION AND LOSS IN THE RB AND RING CURRENT? OR ARE OTHER PHYSICAL PROCESSES INVOLVED? THE METHODOLOGY FOR CLOSURE ON THESE QUESTIONS WILL INVOLVE BOTH DATA ANALYSIS OF VAN ALLEN PROBES AND NOAA POES DATA SETS AND MHD MODELING TECHNIQUES TOGETHER WITH RB PARTICLE SIMULATIONS. FOR A GIVEN EVENT WE WILL: (A) CHARACTERIZE THE STORMTIME WAVE AND PARTICLE ENVIRONMENT AT THE LOCATION OF EACH VAN ALLEN PROBES SPACECRAFT; (B) USE POES PRECIPITATION MEASUREMENTS CONJUGATE TO EACH VAN ALLEN PROBES SATELLITE TO COMPUTE A PROXY FOR WAVE AMPLITUDES AND EXTEND THIS PROXY TO OTHER LOCATIONS TO DEVELOP A TIME-EVOLVING GLOBAL PICTURE OF WAVE ACTIVITY; (C) SCALE APPROPRIATE MODELS OF PITCH ANGLE AND ENERGY DIFFUSION BY THE INFERRED GLOBAL DISTRIBUTION OF WAVE ACTIVITY; (D) CONDUCT GLOBAL MHD/PARTICLE SIMULATIONS OF THE EVOLVING PHASE SPACE DENSITY USING THE CALCULATED LOCAL DIFFUSION COEFFICIENTS AND MEASURED PARTICLE BOUNDARY AND INITIAL CONDITIONS AND COMPARE TO OBSERVATIONS. THE CUTTING-EDGE K2 RADIATION BELT SIMULATION MODEL FEATURED IN THIS STUDY USES A STOCHASTIC DIFFERENTIAL EQUATION (SDE) METHOD TO SIMULATE LOCAL HEATING AND PITCH ANGLE DIFFUSION EFFECTS AND WILL TAKE BOUNDARY AND INITIAL CONDITIONS DIRECTLY FROM VAN ALLEN PROBE AND GEOSYNCHRONOUS MEASUREMENTS. COMPARISONS OF SIMULATED AND OBSERVED PHASE SPACE DENSITY VARIATIONS WILL INDICATE WHETHER SIMPLE DESCRIPTIONS OF RADIATION BELT DYNAMICS ARE GENERALLY SUFFICIENT OR IF OTHER PHYSICAL MECHANISMS MAY UNDERLIE OBSERVED VARIATIONS IN THE TRAPPED PARTICLE DISTRIBUTION. THIS PROPOSAL DIRECTLY ADDRESSES THE DECADAL SURVEY GOAL TO "DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE ... AND [ITS] RESPONSE TO SOLAR AND TERRESTRIAL INPUTS." THROUGH THE USE OF HIGH-FIDELITY OBSERVATIONAL DATA SETS NEW ANALYSIS TECHNIQUES AND A STATE-OF-THE-ART MODELING PARADIGM THIS STUDY WILL BRING CLOSURE TO THE SCIENCE QUESTIONS DETAILED HERE AND PROVIDE A FRESH PERSPECTIVE ON RB AND RING CURRENT DYNAMICS.