GOALS: FIRST WE PROPOSE TO INVESTIGATE THE EFFECTS OF PC 4-5 WAVES (2-22 MHZ) ON THE DEVELOPMENT OF ELECTROMAGNETIC ION CYCLOTRON (EMIC 0.1-5 HZ) WAVES IN THE EARTH'S INNER MAGNETOSPHERE. WE WILL STUDY BOTH THE EFFECT OF EMIC WAVE GROWTH RATE MODULATION BY COMPRESSIONAL PC 4-5 WAVES AND THE NONLINEAR CASCADE OF ELECTROMAGNETIC ENERGY FROM THE PC 4-5 FREQUENCY RANGE INTO THE FREQUENCY RANGE OF EMIC WAVE GENERATION. SECOND WE PROPOSE TO STUDY THE EFFECTS OF EMIC WAVES ON RELATIVISTIC ELECTRON PRECIPITATION IN THE EARTH'S RADIATION BELTS (RBS). BACKGROUND: EMIC WAVES ARE CONSIDERED TO BE ONE OF THE MOST IMPORTANT CAUSES FOR RELATIVISTIC ELECTRON PRECIPITATION FROM THE EARTH'S RBS. CURRENTLY HOWEVER UNDERSTANDING OF EMIC WAVE DEVELOPMENT AND EVOLUTION IN EARTH'S MAGNETOSPHERE IS FAR FROM BEING COMPLETE AND THERE IS NO RELIABLE PHYSICS-BASED MODEL OF EMIC WAVES THAT CAN BE USED IN A REALISTIC MODELING OF RELATIVISTIC ELECTRONS. THE HE-BAND OF EMIC WAVES IS THE DOMINANT BAND OBSERVED IN THE INNER MAGNETOSPHERE AND WAVES ARE USUALLY QUASI-FIELD-ALIGNED THERE. TO BE OBSERVED AS QUASI-FIELD-ALIGNED WAVES SHOULD GROW UP TO AN OBSERVABLE LEVEL DURING ONE PASS THROUGH THE NEAR EQUATORIAL UNSTABLE REGION BECAUSE EVEN IF WAVES RETURN TO THE EQUATOR AFTER REFLECTION FROM THE "BI-ION LATITUDES" (THE LATITUDES WHERE WAVE FREQUENCY MATCHES THE LOCAL O-HE BI-ION FREQUENCY) THEY USUALLY HAVE OBLIQUE NORMALS AND CANNOT BE RE-AMPLIFIED DUE TO THE QUASIFIELD- ALIGNED ION CYCLOTRON INSTABILITY. THE THERMAL BACKGROUND LEVEL FOR EMIC WAVES HOWEVER IS LOW AND WAVES CANNOT REACH AN OBSERVABLE LEVEL DURING ONE PASS IF THEY GROW FROM THIS LEVEL. ONE OF THE POSSIBILITIES TO OVERCOME THIS DRAWBACK IS TO INCREASE THE EMIC WAVE GROWTH RATE COMPARED TO ITS NOMINAL VALUES BY MODULATING THE MAGNETIC FIELD AND/OR PLASMA DENSITY BY COMPRESSIONAL PC 4-5 WAVES. EMIC WAVES HOWEVER ARE OFTEN OBSERVED WHEN THE AMPLITUDES OF COMPRESSIONAL PC 4-5 ARE SMALL. THE OTHER POSSIBILITY IS TO INVOKE SOME NONLINEAR MECHANISM THAT CAN SUPPLY AN ELECTROMAGNETIC SEED FLUCTUATING ENERGY WHICH SUBSTANTIALLY EXCEEDS THE THERMAL BACKGROUND LEVEL IN THE FREQUENCY DOMAIN OF EMIC WAVE GENERATION. AN MHD WAVE-WAVE INTERACTION GENERATES AN ENERGY CASCADE IN THE REGION OF LARGER WAVE NUMBERS AND SO CAN SERVE AS A NEEDED MECHANISM. OUR PRELIMINARY ANALYSIS OF THE VAN ALLEN PROBES AND POLAR SPACECRAFT DATA ACROSS THE PC 1-5 WAVE BANDS SHOWS THAT A NONLINEAR ENERGY CASCADE FROM THE PC 4-5 FREQUENCY RANGE INTO THE FREQUENCY RANGE OF EMIC WAVES IS OBSERVED AND ABLE TO SUPPLY THE NEEDED LEVEL OF NONTHERMAL FLUCTUATIONS THAT GUARANTEES GROWTH OF EMIC WAVES DURING ONE PASS THROUGH THE NEAR EQUATORIAL REGION IF AN ION CYCLOTRON INSTABILITY TAKES PLACE THERE. METHODOLOGY: TO ACHIEVE THE FIRST GOAL WE WILL COMBINE THE ANALYSIS OF VAN ALLEN PROBES DATA ACROSS THE PC 1-5 BANDS WITH THE CAPABILITIES OF TWO GLOBAL MODELS THE LYON-FEDDER-MOBARRY MHD MODEL OF THE MAGNETOSPHERE AND OUR MODEL OF RING CURRENT (RC) IONS AND EMIC WAVES . TO ACHIEVE OUR SECOND GOAL WE WILL USE THE COMPREHENSIVE INNER MAGNETOSPHERE-IONOSPHERE GLOBAL MODEL OF RELATIVISTIC ELECTRONS THE GLOBAL RC-EMIC WAVE MODEL AND ANALYSIS OF THE RELATIVISTIC ELECTRON FLUXES AND EMIC WAVES OBSERVED BY VAN ALLEN PROBES. DATA: WE WILL USE DATA FROM TWO VAN ALLEN PROBES: 1) EMFISIS FOR MAGNETIC FIELD AND ELECTRON NUMBER DENSITY ESTIMATED FROM THE UPPER HYBRID FREQUENCY 2) EFW FOR ELECTRON NUMBER DENSITY ESTIMATED FROM SPACECRAFT POTENTIAL 3) ECT/HOPE FOR DISTRIBUTION FUNCTIONS OF ENERGETIC IONS AND ION COMPOSITION AND 4) ECT/MAGEIS AND ECT/REPT FOR FLUXES OF RELATIVISTIC ELECTRONS. RELEVANCE: THIS PROPOSAL IS RELEVANT TO THE DECADAL SURVEY GOALS "2. DETERMINE THE DYNAMICS AND COUPLING OF EARTH'S MAGNETOSPHERE IONOSPHERE AND ATMOSPHERE AND THEIR RESPONSE TO SOLAR AND TERRESTRIAL INPUTS" AND "4. DISCOVER AND CHARACTERIZE FUNDAMENTAL PROCESSES THAT OCCUR BOTH WITHIN THE HELIOSPHERE AND THROUGHOUT THE UNIVERSE."