THE SCIENCE OBJECTIVE OF THIS STUDY IS TO UNDERSTAND THE MESO-SCALE PLASMA TRANSPORT PROCESSES DRIVEN BY THE THREE-DIMENSIONAL (3- D) NONLINEAR INTERACTION BETWEEN KELVIN-HELMHOLTZ INSTABILITY (KHI) AND MAGNETIC RECONNECTION AT THE EARTH'S MAGNETOPAUSE. IT HAS BEEN WELL DEMONSTRATED THAT BOTH RECONNECTION AND KHI ALONE CAN PLAY THE CRITICAL ROLES TO THE SOLAR WIND-MAGNETOSPHERE COUPLING UNDER DIFFERENT INTERPLANETARY MAGNETIC FIELD (IMF) CONDITIONS. RECENTLY BOTH NUMERICAL SIMULATION AND IN-SITU OBSERVATIONAL STUDIES INDICATED THE FUNDAMENTAL IMPORTANCE OF THE NONLINEAR INTERACTION BETWEEN KHI AND RECONNECTION IN A 3-D CONFIGURATION IN ALL IMF ORIENTATIONS. HOWEVER THIS NONLINEAR INTERACTION HAS NOT BE FULLY UNDERSTAND DUE TO ITS INTRINSICALLY COMPLEX STRUCTURE. THUS A SYSTEMATIC APPROACH TO OUR SCIENCE OBJECTIVE IS ADDRESSING THE FOLLOWING THREE COMPELLING SCIENCE QUESTIONS BY SYNERGY BOTH NUMERICAL SIMULATION AND IN-SITU OBSERVATIONAL DATA.1. HOW EFFICIENTLY IS THE PLASMA TRANSPORTED BY THE 3-D NONLINEAR INTERACTION BETWEEN KHI AND RECONNECTION UNDER DIFFERENT IMF CONDITIONS? 2. HOW IS PLASMA NONADIABATICALLY HEATED DURING THE NONLINEAR INTERACTION IN DIFFERENT IMF CONDITIONS? 3. WHAT ARE THE ROBUST OBSERVATIONAL SIGNATURES OF THIS NONLINEAR INTERACTION IN DIFFERENT IMF CONDITIONS? THOSE QUESTIONS REQUIRE THE LOCAL PROCESSES (I.E. RECONNECTION AND KHI) TO BE FULLY RESOLVED WHICH IS A SIGNIFICANT CHALLENGE FOR GLOBAL SIMULATIONS. MEANWHILE THE NONADIABATICALLY HEATED PLASMA MUST FILL THE VOLUME WHOSE DIMENSION IS ON THE ORDER OF AN EARTH RADIUS. THIS INDICATES THAT THE SIMULATION DOMAIN MUST BE MUCH LARGER THAN THE ION INERTIAL LENGTH WHICH IS NOT SUITABLE FOR PARTICLE-IN-CELL SIMULATIONS. OUR MESOSCALE 3-D SIMULATION (MHD HALL MHD AND HYBRID SIMULATION) DOMAIN COVERS ABOUT 2 TO 6 EARTH RADII IN ALL DIRECTIONS WITH A BEST RESOLUTION OF 0.1 OF THE ION INERTIAL LENGTH WHICH ADEQUATELY MATCHES THE REQUIREMENT. THE RATES FOR THE TRANSPORT OF MASS MOMENTUM ENERGY AND MAGNETIC FLUX UNDER DIFFERENT IMF CONDITIONS WILL BE ESTIMATED BASED ON THOSE SIMULATION RESULTS. IT HAS BEEN DEMONSTRATED THAT THE STRONG NONADIABATIC HEATING OF PLASMA DURING ITS PENETRATION FROM THE MAGNETOSHEATH INTO THE MAGNETOSPHERE CANNOT BE EXPLAINED BY HEATING THROUGH MAGNETIC RECONNECTION ALONE. PLAUSIBLE NONADIABATIC HEATING MECHANISMS ASSOCIATED WITH THE KHI INCLUDE FOR EXAMPLE ENERGETIC MAGNETOSHEATH PARTICLES CAN BE TRAPPED IN THE MAGNETOSPHERE BY INTERMITTENT RECONNECTION FOR NORTHWARD IMF CONDITIONS. THIS PROCESS FILTERS HIGH ENERGY PARTICLES AND CAN INCREASE THE SPECIFIC ENTROPY OF THE NEWLY CAPTURED PLASMA IN THE MAGNETOSPHERE. THUS TEST PARTICLES IN THE FLUID SIMULATION RESULTS AND HYBRID SIMULATIONS WILL BE USED TO INVESTIGATE THE ASSOCIATED MESO-SCALE NONADIABATIC HEATING MECHANISMS DURING TRANSPORT. OUR THEORY/SIMULATION RESULTS WILL BE COMPARED WITH OBSERVATIONAL DATA. CO-I S. ERIKSSON HAVE ALREADY IDENTIFIED SEVERAL RECONNECTION EMBEDDED IN KHI EVENTS IN THEMIS AND MMS DATA.THE OBSERVED ION DISTRIBUTIONS CAN BE COMPARED WITH HYBRID SIMULATION RESULTS DIRECTLY OR THE RECONSTRUCTION OF PARTICLE DISTRIBUTIONS BASED ON LIOUVILLE'S THEORY BY REVERSE TRACING THE TEST PARTICLES IN THE FLUID SIMULATION. ALL NUMERICAL SIMULATION CODES AND DIAGNOSTIC TOOLS HAVE BEEN DEVELOPED AND HAVE BEEN APPLIED TO THE OTHER STUDIES. THE OBSERVATIONAL DATA FROM THEMIS CLUSTER AND MMS DATA ARE AVAILABLE FROM THE NASA S SPDF. THIS PROPOSAL BELONGS TO THE BROAD CATEGORIES: MAGNETOSPHERE AND SCIENCE AREAS: SOLAR WIND MAGNETOSPHERE COUPLING. THUS THE PROPOSAL IS BY DEFINITION RELEVANT TO 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.