ON THE EFFECTIVENESS OF INWARD RADIAL DIFFUSION IN THE ENERGIZATION OF OUTER BELT ELECTRONS - BASED ON DATA FROM THE VAN ALLEN PROBES AND THEMIS MISSIONSWE PROPOSE TO DETERMINE THE CONTRIBUTION OF RADIAL DIFFUSION TO THE ENERGIZATION OF OUTER RADIATION BELT ELECTRONS. RADIAL DIFFUSION LIKE ANY DIFFUSION PROCESS IS STOCHASTIC: MANY SMALL FLUCTUATIONS ADD TO GIVE AN OVERALL MACROSCOPIC CHANGE. RADIAL DIFFUSION OF RADIATION BELT ELECTRONS IS DRIVEN BY MAGNETIC AND ELECTRIC FIELD FLUCTUATIONS ON A TIME SCALE OF THE DRIFT PERIOD OF THE ELECTRONS (10 60 MIN DEPENDING ON THE ENERGY) AND ON A SPATIAL SCALE THAT IS A SIGNIFICANT FRACTION OF THE MAGNETOSPHERE. THUS DURING INTERVALS WHEN THE ELECTRON FLUX IS RISING THE MAGNETIC AND ELECTRIC FIELD FLUCTUATIONS ALONG THE ELECTRONS DRIFT MOTION WILL IMPOSE FLUCTUATIONS ON THE ELECTRONS WHICH HAVE BEEN CLEARLY MEASURED BY VAN ALLEN PROBES/MAGEIS INSTRUMENT THAT HAS A VERY FINE ENERGY RESOLUTION IN ELECTRON FLUXES.THE PARTICLE DATA FOR THE PROPOSED STUDY WILL BE MAINLY FROM THE MAGEIS MEASUREMENTS WHILE THE FIELD DATA WILL BE FROM BOTH VAN ALLEN PROBES AND THEMIS MISSIONS. DATA ANALYSIS IS THE MAJOR EFFORT OF THIS PROPOSED STUDY BUT TO REACH ANY QUANTITATIVE CONCLUSION MODELING EFFORTS USING TEST PARTICLE SIMULATION ARE NEEDED. TEST PARTICLE GUIDING CENTER CODES HAVE BEEN WELL DEVELOPED BY THE PI ANDCO-I AND HAVE BEEN USED TO INVESTIGATE ELECTRON RADIATION BELT FORMATION AFTER A STRONG INTERPLANETARY SHOCK IMPACTED ON THE EARTH TO MODEL SUBSTORM INJECTIONS AND TO SIMULATE RADIAL DIFFUSION OF ENERGETIC (MEV) ELECTRONS THROUGH A MODEL OF FLUCTUATING ELECTRIC AND MAGNETIC FIELDS.WE WILL FIRST ANALYZE THE MAGNETIC AND ELECTRIC FIELD DATA FOR CHOSEN EVENTS TO ESTABLISH THE FIELD MODEL AND ANALYZE THE ELECTRON DATA OF THE SAME EVENTS TO ESTABLISH THE ELECTRON FLUX AT DIFFERENT L-SHELLS AND THEIR PHASE SPACE DENSITY RADIAL PROFILES. WE WILL THEN RUN TEST PARTICLE SIMULATIONS TO DETERMINE THE LEVEL OF ELECTRON FLUCTUATIONS TO BE EXPECTED FOR A GIVEN LEVEL OF RADIAL DIFFUSION. IN THE TEST PARTICLE SIMULATIONS MILLIONS OF ELECTRONS AT VARIOUS L-SHELLS WILL BE SUBJECTED TO THE ELECTRIC AND MAGNETIC FIELD FLUCTUATIONS. THIS WILL PRODUCE RADIAL DIFFUSION AND ALSO FLUCTUATION IN THE ELECTRON FLUX AT ALL LOCAL TIMES EVEN AT LOCAL TIMES WHERE THERE MAY BE NO FIELD FLUCTUATIONS. THE ADVANTAGE OF USING TEST PARTICLE SIMULATIONS IS THAT WE CAN MAKE THE FLUCTUATION LEVEL IN THE SIMULATED ELECTRON FLUX TO MATCH THE MEASURED ELECTRON FLUX UNDER REALISTIC FIELD FLUCTUATIONS AND SUBSEQUENTLY WE CAN CALCULATE THE RADIAL DIFFUSION RATE IN THE SIMULATION.THUS WE WILL KNOW THE ACTUAL RADIAL DIFFUSION RATE IN THE DATA EVENTS THAT WE ANALYZED. COMBINING THE ACTUAL MEASURED ELECTRON FLUX AT A GIVEN L-SHELL AND THE PHASE SPACE DENSITY RADIAL PROFILE WITH THE DETERMINED RADIAL DIFFUSION RATE WE WILL THEN BE ABLE TO DETERMINE THE CONTRIBUTION OF RADIAL DIFFUSION TO THE ENERGIZATION OF THE MEASURED ELECTRON FLUX.THE TWO POSSIBLE SOURCES OF OUTER RADIATION BELT ELECTRON ARE LESS ENERGETIC ELECTRONS AT LARGER L-SHELLS ENERGIZED BY INWARD RADIAL DIFFUSION OR LESS ENERGETIC ELECTRONS ON THE SAME L-SHELL ENERGIZED LOCALLY BY WAVE-PARTICLE INTERACTIONS. IN BOTH CASES LOWER ENERGY ELECTRONS USUALLY HAVE A SUBSTANTIALLY LARGER PHASE SPACE DENSITY AND THUS CAN BE A SOURCE OF THE MORE ENERGETIC ELECTRONS. HOWEVER THE RELATIVE CONTRIBUTION OF THE TWO ACCELERATION MECHANISMS IS DIFFICULT TO DETERMINE. A TOP PRIORITY OF VAN ALLEN PROBES MISSION IS TO DIFFERENTIATE THESE TWO ACCELERATION MECHANISMS.THE ADVANTAGES OF THIS METICULOUS METHODOLOGY WERE UNRECOGNIZED UNTIL THE SOPHISTICATED MEASUREMENTS FROM THE VAN ALLEN PROBES MISSION SHOWED CLEAR FLUCTUATIONS AROUND THE DRIFT PERIODS OF THE ELECTRONS. OUR PROPOSED STUDY WILL HELP TO ACCOMPLISH ONE OF THE KEY VAN ALLEN PROBES MISSION GOALS. OUR PROPOSED STUDY IS ALSO DIRECTLY RELATED TO ONE OF THE DECADAL SURVEY GOALS IN SOLAR WIND MAGNETOSPHERE INTERACTION (SWMI)