PARTICLE FLUXES IN EARTH S RADIATION BELTS ARE HIGHLY VARIABLE DETERMINED BY A COMPLEX BALANCE BETWEEN ACCELERATION AND LOSS PROCESSES. THE TWO MAIN PROCESSES THAT CAUSE ELECTRON LOSS IN THE RADIATION BELTS ARE LOSSES TO THE MAGNETOPAUSE AND SCATTERING INTO THE ATMOSPHERE THROUGH WAVE-PARTICLE INTERACTION. WAVE-PARTICLE INTERACTION BETWEEN RELATIVISTIC ELECTRONS AND ELECTROMAGNETIC ION CYCLOTRON (EMIC) WAVES WAS FIRST SUGGESTED AS A MAJOR LOSS MECHANISM IN THE RADIATION BELTS BY THORNE AND KENNEL IN 1971 AND REMAINS ONE OF THE MOST HIGHLY DEBATED LOSS PROCESSES CONTRIBUTING TO THE VARIABILITY OF EARTH S RADIATION BELTS. THEORETICAL STUDIES SHOW UNDER CERTAIN CONDITIONS EMIC WAVES CAN RESULT IN STRONG LOSS OF MULTI-MEV ELECTRONS FROM THE RADIATION BELTS. OBSERVATIONAL STUDIES SHOW THE EFFECTIVENESS OF EMIC WAVES AS A MAJOR LOSS MECHANISM IS STILL NOT QUANTITATIVELY UNDERSTOOD. RECENT OBSERVATIONS OF ELECTRON PRECIPITATION FROM MISSIONS SUCH AS THE BALLOON ARRAY FOR RADIATION BELT RELATIVISTIC ELECTRON LOSS (BARREL) SUGGEST THAT EMIC WAVES CAN CAUSE ELECTRON PRECIPITATION OVER A BROAD ENERGY RANGE EXTENDING DOWN TO 100 S OF KEV. HOWEVER PRECIPITATION DOES NOT OCCUR EVERYWHERE THAT WAVES ARE OBSERVED AND IS CONFINED TO NARROW MAGNETIC LOCAL TIME (MLT) REGIONS IN THE DUSK-SIDE MAGNETOSPHERE. THIS PROPOSAL EXPANDS OUR UNDERSTANDING OF THE EARTH S RADIATION BELT PARTICLE DYNAMICS AND WILL INVESTIGATE THE OVERALL EFFECTIVENESS OF ELECTROMAGNETIC ION CYCLOTRON (EMIC) WAVES TO PRECIPITATE RELATIVISTIC ELECTRONS OVER A BROAD ENERGY RANGE (100 S KEV MULTI-MEV) INTO THE ATMOSPHERE. THEREFORE WE WILL DETERMINE IF THE DISTRIBUTION AND SPATIAL SCALE OF OBSERVED DUSK-SIDE RELATIVISTIC ELECTRON PRECIPITATION IS A CONSEQUENCE OF THE WAVE-PARTICLE INTERACTION BETWEEN EMIC WAVES AND RADIATION BELT RELATIVISTIC ELECTRONS. WE WILL ALSO INVESTIGATE THE OCCURRENCE RATE OF THE PLASMA CONDITIONS AND EMIC WAVE PROPERTIES WHICH ARE CONDUCIVE TO PRECIPITATION. THIS PROPOSED WORK ADDRESSES ONE OF FOUR HIGH-LEVEL SCIENCE GOALS FROM THE HELIOPHYSICS DECADAL SURVEY: DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE IONOSPHERE AND ATMOSPHERE AND THEIR RESPONSE TO SOLAR AND TERRESTRIAL INPUTS .