4 THE OBJECTIVE OF THIS STUDY IS TO IDENTIFY AND CHARACTERIZE THE PRIMARY PLASMA MOTIONS RESPONSIBLE FOR THE ONSET OF EXPLOSIVE MAGNETOTAIL ACTIVITY DURING SUBSTORMS AND BURSTY BULK FLOWS. THE EXPLOSIVE RELEASE OF ENERGY STORED IN THE MAGNETOTAIL IS A KEY PROCESS IN THE SOLAR WIND-MAGNETOSPHERE INTERACTION. IT DEVELOPS IN 3D OVER A BROAD RANGE OF SCALES FROM ION AND ELECTRON GYRORADII TO GLOBAL SCALES, INVOLVES BOTH MHD AND KINETIC PROCESSES AND DIFFERENT PLASMA EIGENMODES, INCLUDING MAGNETIC RECONNECTION, BUOYANCY AND FLAPPING MOTIONS. THEREFORE ITS FIRST-PRINCIPLES DESCRIPTION REQUIRES FULLY KINETIC 3D SIMULATIONS. TO BE FEASIBLE AND YIELD SIGNIFICANT RESULTS THE SIMULATIONS MUST BE CONSTRAINED BY DATA ON THE TAIL EXPLOSIONS AND ON THE TAIL STRUCTURE PRIOR TO THE EXPLOSION. IN PARTICULAR, ACCUMULATION OF MAGNETIC FLUX IN THE TAIL GIVES EITHER RECONNECTION- OR BUOYANCY-DOMINATED PICTURE OF EXPLOSIONS, WHEN IT IS SIMULATED BY CODES WITH OPEN OR CLOSED BOUNDARIES THAT DESCRIBE NEAR-EARTH OR MORE DISTANT TAIL REGIONS, RESPECTIVELY. WHICH OF THESE TWO THEORETICAL PICTURES, EACH OF WHICH IS LIMITED IN ITS SPATIAL EXTENSION TO A FEW EARTH RADII, DESCRIBES THE ACTUAL DYNAMICS OF THE GLOBAL MAGNETOTAIL DEPENDS ON THE DETAILS OF THE MAGNETIC FLUX DISTRIBUTION ALONG THE TAIL PRIOR TO THE ONSET. THUS, THE FUNDAMENTAL SCIENCE QUESTION, WHAT ARE THE PRIMARY MECHANISMS OF THE EXPLOSIVE PROCESSES IN THE MAGNETOTAIL DEPENDING ON ITS GLOBAL PRE-ONSET STRUCTURE AND SOLAR WIND DRIVING? CAN ONLY BE ANSWERED USING GLOBAL TAIL MODELS WHOSE STRUCTURE IS GUIDED BY OBSERVATIONS. IN THIS PROJECT WE PROPOSE TO USE OBSERVATIONS TO CONSTRAIN A NEW CLASS OF GLOBAL MAGNETOTAIL EQUILIBRIA, INCLUDING EFFECTS OF THE DIPOLE FIELD AND THE MAGNETIC FLUX ACCUMULATION, AND TO ASSESS THE STRENGTH OF EXTERNAL DRIVING. THEN WE WILL PERFORM 3D PIC SIMULATIONS OF THE TERRESTRIAL MAGNETOTAIL WITH THE EXTENSION ALONG THE TAIL TO GLOBAL SCALES (UP TO ~10RE) THUS REDUCING THE DEPENDENCE OF THE RESULTS ON THE TYPE OF THE BOUNDARY CONDITIONS. WE WILL USE DATA FROM CLUSTER, THEMIS AND GEOTAIL TO COMPARE THE RESULTS OF SIMULATIONS WITH OBSERVATIONS OF BURSTY MAGNETOTAIL PROCESSES AND TO ADJUST THE PRE-ONSET TAIL EQUILIBRIA AND SIMULATION PARAMETERS. IN ADDITION, MHD SIMULATIONS WILL BE USED TO COMPLEMENT INHERENTLY LOCALIZED OBSERVATIONS IN ASSESSING THE GLOBAL PRE-ONSET TAIL STRUCTURE AND DRIVING FORCE DISTRIBUTIONS AS WELL AS TO UNDERSTAND THE RELATIVE ROLE OF IDEAL AND KINETIC INSTABILITIES. THE COMBINATION OF KINETIC AND REGIONAL MHD SIMULATIONS WILL ALSO BE USED TO FORMULATE A REDUCED KINETIC DESCRIPTION OF THE TAIL ACTIVITY MECHANISMS SUITABLE FOR GLOBAL MHD MODELS. MAGNETIC RECONNECTION, BUOYANCY AND FLAPPING MOTIONS ARE UNIVERSAL PROCESSES IN SPACE PLASMAS, INCLUDING MAGNETOSPHERES OF OTHER PLANETS, SOLAR AND STELLAR CORONAE AS WELL AS BLACK HOLE ACCRETION DISCS. THIS STUDY WILL USE DATA FROM CURRENT SINGLE- AND MULTISPACECRAFT NASA MISSIONS TO DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE AND THE SOLAR WIND, TO CHARACTERIZE KEY PROCESSES THAT OCCUR ALMOST EVERYWHERE IN SPACE PLASMAS. THUS, IT DIRECTLY ADDRESSES KEY SCIENCE GOAL 2 OF THE 2013-2022 HELIOPHYSICS DECADAL SURVEY DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE, IONOSPHERE, AND ATMOSPHERE AND THEIR RESPONSE TO SOLAR AND TERRESTRIAL INPUTS AND GOAL 4 DISCOVER AND CHARACTERIZE FUNDAMENTAL PROCESSES THAT OCCUR BOTH WITHIN THE HELIOSPHERE AND THROUGHOUT THE UNIVERSE . IT WILL ALSO HELP IN GUIDING FUTURE NASA MISSIONS MMS AND SOLAR PROBE PLUS. IT INCLUDES RESEARCH TRAINING FOR STUDENT SUMMER INTERNS VIA THE NASA/APL SUMMER INTERN PROGRAM. Funding Only Action ($794) 2/11/20 Not listed THE OBJECTIVE OF THIS STUDY IS TO IDENTIFY AND CHARACTERIZE THE PRIMARY PLASMA MOTIONS RESPONSIBLE FOR THE ONSET OF EXPLOSIVE MAGNETOTAIL ACTIVITY DURING SUBSTORMS AND BURSTY BULK FLOWS. THE EXPLOSIVE RELEASE OF ENERGY STORED IN THE MAGNETOTAIL IS A KEY PROCESS IN THE SOLAR WIND-MAGNETOSPHERE INTERACTION. IT DEVELOPS IN 3D OVER A BROAD RANGE OF SCALES FROM ION AND ELECTRON GYRORADII TO GLOBAL SCALES INVOLVES BOTH MHD AND KINETIC PROCESSES AND DIFFERENT PLASMA EIGENMODES INCLUDING MAGNETIC RECONNECTION BUOYANCY AND FLAPPING MOTIONS. THEREFORE ITS FIRST-PRINCIPLES DESCRIPTION REQUIRES FULLY KINETIC 3D SIMULATIONS. TO BE FEASIBLE AND YIELD SIGNIFICANT RESULTS THE SIMULATIONS MUST BE CONSTRAINED BY DATA ON THE TAIL EXPLOSIONS AND ON THE TAIL STRUCTURE PRIOR TO THE EXPLOSION. IN PARTICULAR ACCUMULATION OF MAGNETIC FLUX IN THE TAIL GIVES EITHER RECONNECTION- OR BUOYANCY-DOMINATED PICTURE OF EXPLOSIONS WHEN IT IS SIMULATED BY CODES WITH OPEN OR CLOSED BOUNDARIES THAT DESCRIBE NEAR-EARTH OR MORE DISTANT TAIL REGIONS RESPECTIVELY. WHICH OF THESE TWO THEORETICAL PICTURES EACH OF WHICH IS LIMITED IN ITS SPATIAL EXTENSION TO A FEW EARTH RADII DESCRIBES THE ACTUAL DYNAMICS OF THE GLOBAL MAGNETOTAIL DEPENDS ON THE DETAILS OF THE MAGNETIC FLUX DISTRIBUTION ALONG THE TAIL PRIOR TO THE ONSET. THUS THE FUNDAMENTAL SCIENCE QUESTION WHAT ARE THE PRIMARY MECHANISMS OF THE EXPLOSIVE PROCESSES IN THE MAGNETOTAIL DEPENDING ON ITS GLOBAL PRE-ONSET STRUCTURE AND SOLAR WIND DRIVING? CAN ONLY BE ANSWERED USING GLOBAL TAIL MODELS WHOSE STRUCTURE IS GUIDED BY OBSERVATIONS. IN THIS PROJECT WE PROPOSE TO USE OBSERVATIONS TO CONSTRAIN A NEW CLASS OF GLOBAL MAGNETOTAIL EQUILIBRIA INCLUDING EFFECTS OF THE DIPOLE FIELD AND THE MAGNETIC FLUX ACCUMULATION AND TO ASSESS THE STRENGTH OF EXTERNAL DRIVING. THEN WE WILL PERFORM 3D PIC SIMULATIONS OF THE TERRESTRIAL MAGNETOTAIL WITH THE EXTENSION ALONG THE TAIL TO GLOBAL SCALES (UP TO ~10RE) THUS REDUCING THE DEPENDENCE OF THE RESULTS ON THE TYPE OF THE BOUNDARY CONDITIONS. WE WILL USE DATA FROM CLUSTER THEMIS AND GEOTAIL TO COMPARE THE RESULTS OF SIMULATIONS WITH OBSERVATIONS OF BURSTY MAGNETOTAIL PROCESSES AND TO ADJUST THE PRE-ONSET TAIL EQUILIBRIA AND SIMULATION PARAMETERS. IN ADDITION MHD SIMULATIONS WILL BE USED TO COMPLEMENT INHERENTLY LOCALIZED OBSERVATIONS IN ASSESSING THE GLOBAL PRE-ONSET TAIL STRUCTURE AND DRIVING FORCE DISTRIBUTIONS AS WELL AS TO UNDERSTAND THE RELATIVE ROLE OF IDEAL AND KINETIC INSTABILITIES. THE COMBINATION OF KINETIC AND REGIONAL MHD SIMULATIONS WILL ALSO BE USED TO FORMULATE A REDUCED KINETIC DESCRIPTION OF THE TAIL ACTIVITY MECHANISMS SUITABLE FOR GLOBAL MHD MODELS. MAGNETIC RECONNECTION BUOYANCY AND FLAPPING MOTIONS ARE UNIVERSAL PROCESSES IN SPACE PLASMAS INCLUDING MAGNETOSPHERES OF OTHER PLANETS SOLAR AND STELLAR CORONAE AS WELL AS BLACK HOLE ACCRETION DISCS. THIS STUDY WILL USE DATA FROM CURRENT SINGLE- AND MULTISPACECRAFT NASA MISSIONS TO DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE AND THE SOLAR WIND TO CHARACTERIZE KEY PROCESSES THAT OCCUR ALMOST EVERYWHERE IN SPACE PLASMAS. THUS IT DIRECTLY ADDRESSES KEY SCIENCE GOAL 2 OF THE 2013-2022 HELIOPHYSICS DECADAL SURVEY DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE IONOSPHERE AND ATMOSPHERE AND THEIR RESPONSE TO SOLAR AND TERRESTRIAL INPUTS AND GOAL 4 DISCOVER AND CHARACTERIZE FUNDAMENTAL PROCESSES THAT OCCUR BOTH WITHIN THE HELIOSPHERE AND THROUGHOUT THE UNIVERSE . IT WILL ALSO HELP IN GUIDING FUTURE NASA MISSIONS MMS AND SOLAR PROBE PLUS. IT INCLUDES RESEARCH TRAINING FOR STUDENT SUMMER INTERNS VIA THE NASA/APL SUMMER INTERN PROGRAM. ($794) 2/11/20 3 THE OBJECTIVE OF THIS STUDY IS TO IDENTIFY AND CHARACTERIZE THE PRIMARY PLASMA MOTIONS RESPONSIBLE FOR THE ONSET OF EXPLOSIVE MAGNETOTAIL ACTIVITY DURING SUBSTORMS AND BURSTY BULK FLOWS. THE EXPLOSIVE RELEASE OF ENERGY STORED IN THE MAGNETOTAIL IS A KEY PROCESS IN THE SOLAR WIND-MAGNETOSPHERE INTERACTION. IT DEVELOPS IN 3D OVER A BROAD RANGE OF SCALES FROM ION AND ELECTRON GYRORADII TO GLOBAL SCALES, INVOLVES BOTH MHD AND KINETIC PROCESSES AND DIFFERENT PLASMA EIGENMODES, INCLUDING MAGNETIC RECONNECTION, BUOYANCY AND FLAPPING MOTIONS. THEREFORE ITS FIRST-PRINCIPLES DESCRIPTION REQUIRES FULLY KINETIC 3D SIMULATIONS. TO BE FEASIBLE AND YIELD SIGNIFICANT RESULTS THE SIMULATIONS MUST BE CONSTRAINED BY DATA ON THE TAIL EXPLOSIONS AND ON THE TAIL STRUCTURE PRIOR TO THE EXPLOSION. IN PARTICULAR, ACCUMULATION OF MAGNETIC FLUX IN THE TAIL GIVES EITHER RECONNECTION- OR BUOYANCY-DOMINATED PICTURE OF EXPLOSIONS, WHEN IT IS SIMULATED BY CODES WITH OPEN OR CLOSED BOUNDARIES THAT DESCRIBE NEAR-EARTH OR MORE DISTANT TAIL REGIONS, RESPECTIVELY. WHICH OF THESE TWO THEORETICAL PICTURES, EACH OF WHICH IS LIMITED IN ITS SPATIAL EXTENSION TO A FEW EARTH RADII, DESCRIBES THE ACTUAL DYNAMICS OF THE GLOBAL MAGNETOTAIL DEPENDS ON THE DETAILS OF THE MAGNETIC FLUX DISTRIBUTION ALONG THE TAIL PRIOR TO THE ONSET. THUS, THE FUNDAMENTAL SCIENCE QUESTION, WHAT ARE THE PRIMARY MECHANISMS OF THE EXPLOSIVE PROCESSES IN THE MAGNETOTAIL DEPENDING ON ITS GLOBAL PRE-ONSET STRUCTURE AND SOLAR WIND DRIVING? CAN ONLY BE ANSWERED USING GLOBAL TAIL MODELS WHOSE STRUCTURE IS GUIDED BY OBSERVATIONS. IN THIS PROJECT WE PROPOSE TO USE OBSERVATIONS TO CONSTRAIN A NEW CLASS OF GLOBAL MAGNETOTAIL EQUILIBRIA, INCLUDING EFFECTS OF THE DIPOLE FIELD AND THE MAGNETIC FLUX ACCUMULATION, AND TO ASSESS THE STRENGTH OF EXTERNAL DRIVING. THEN WE WILL PERFORM 3D PIC SIMULATIONS OF THE TERRESTRIAL MAGNETOTAIL WITH THE EXTENSION ALONG THE TAIL TO GLOBAL SCALES (UP TO ~10RE) THUS REDUCING THE DEPENDENCE OF THE RESULTS ON THE TYPE OF THE BOUNDARY CONDITIONS. WE WILL USE DATA FROM CLUSTER, THEMIS AND GEOTAIL TO COMPARE THE RESULTS OF SIMULATIONS WITH OBSERVATIONS OF BURSTY MAGNETOTAIL PROCESSES AND TO ADJUST THE PRE-ONSET TAIL EQUILIBRIA AND SIMULATION PARAMETERS. IN ADDITION, MHD SIMULATIONS WILL BE USED TO COMPLEMENT INHERENTLY LOCALIZED OBSERVATIONS IN ASSESSING THE GLOBAL PRE-ONSET TAIL STRUCTURE AND DRIVING FORCE DISTRIBUTIONS AS WELL AS TO UNDERSTAND THE RELATIVE ROLE OF IDEAL AND KINETIC INSTABILITIES. THE COMBINATION OF KINETIC AND REGIONAL MHD SIMULATIONS WILL ALSO BE USED TO FORMULATE A REDUCED KINETIC DESCRIPTION OF THE TAIL ACTIVITY MECHANISMS SUITABLE FOR GLOBAL MHD MODELS. MAGNETIC RECONNECTION, BUOYANCY AND FLAPPING MOTIONS ARE UNIVERSAL PROCESSES IN SPACE PLASMAS, INCLUDING MAGNETOSPHERES OF OTHER PLANETS, SOLAR AND STELLAR CORONAE AS WELL AS BLACK HOLE ACCRETION DISCS. THIS STUDY WILL USE DATA FROM CURRENT SINGLE- AND MULTISPACECRAFT NASA MISSIONS TO DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE AND THE SOLAR WIND, TO CHARACTERIZE KEY PROCESSES THAT OCCUR ALMOST EVERYWHERE IN SPACE PLASMAS. THUS, IT DIRECTLY ADDRESSES KEY SCIENCE GOAL 2 OF THE 2013-2022 HELIOPHYSICS DECADAL SURVEY DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE, IONOSPHERE, AND ATMOSPHERE AND THEIR RESPONSE TO SOLAR AND TERRESTRIAL INPUTS AND GOAL 4 DISCOVER AND CHARACTERIZE FUNDAMENTAL PROCESSES THAT OCCUR BOTH WITHIN THE HELIOSPHERE AND THROUGHOUT THE UNIVERSE . IT WILL ALSO HELP IN GUIDING FUTURE NASA MISSIONS MMS AND SOLAR PROBE PLUS. IT INCLUDES RESEARCH TRAINING FOR STUDENT SUMMER INTERNS VIA THE NASA/APL SUMMER INTERN PROGRAM. Other Administrative Action $0 6/1/18 Not listed THE OBJECTIVE OF THIS STUDY IS TO IDENTIFY AND CHARACTERIZE THE PRIMARY PLASMA MOTIONS RESPONSIBLE FOR THE ONSET OF EXPLOSIVE MAGNETOTAIL ACTIVITY DURING SUBSTORMS AND BURSTY BULK FLOWS. THE EXPLOSIVE RELEASE OF ENERGY STORED IN THE MAGNETOTAIL IS A KEY PROCESS IN THE SOLAR WIND-MAGNETOSPHERE INTERACTION. IT DEVELOPS IN 3D OVER A BROAD RANGE OF SCALES FROM ION AND ELECTRON GYRORADII TO GLOBAL SCALES INVOLVES BOTH MHD AND KINETIC PROCESSES AND DIFFERENT PLASMA EIGENMODES INCLUDING MAGNETIC RECONNECTION BUOYANCY AND FLAPPING MOTIONS. THEREFORE ITS FIRST-PRINCIPLES DESCRIPTION REQUIRES FULLY KINETIC 3D SIMULATIONS. TO BE FEASIBLE AND YIELD SIGNIFICANT RESULTS THE SIMULATIONS MUST BE CONSTRAINED BY DATA ON THE TAIL EXPLOSIONS AND ON THE TAIL STRUCTURE PRIOR TO THE EXPLOSION. IN PARTICULAR ACCUMULATION OF MAGNETIC FLUX IN THE TAIL GIVES EITHER RECONNECTION- OR BUOYANCY-DOMINATED PICTURE OF EXPLOSIONS WHEN IT IS SIMULATED BY CODES WITH OPEN OR CLOSED BOUNDARIES THAT DESCRIBE NEAR-EARTH OR MORE DISTANT TAIL REGIONS RESPECTIVELY. WHICH OF THESE TWO THEORETICAL PICTURES EACH OF WHICH IS LIMITED IN ITS SPATIAL EXTENSION TO A FEW EARTH RADII DESCRIBES THE ACTUAL DYNAMICS OF THE GLOBAL MAGNETOTAIL DEPENDS ON THE DETAILS OF THE MAGNETIC FLUX DISTRIBUTION ALONG THE TAIL PRIOR TO THE ONSET. THUS THE FUNDAMENTAL SCIENCE QUESTION WHAT ARE THE PRIMARY MECHANISMS OF THE EXPLOSIVE PROCESSES IN THE MAGNETOTAIL DEPENDING ON ITS GLOBAL PRE-ONSET STRUCTURE AND SOLAR WIND DRIVING? CAN ONLY BE ANSWERED USING GLOBAL TAIL MODELS WHOSE STRUCTURE IS GUIDED BY OBSERVATIONS. IN THIS PROJECT WE PROPOSE TO USE OBSERVATIONS TO CONSTRAIN A NEW CLASS OF GLOBAL MAGNETOTAIL EQUILIBRIA INCLUDING EFFECTS OF THE DIPOLE FIELD AND THE MAGNETIC FLUX ACCUMULATION AND TO ASSESS THE STRENGTH OF EXTERNAL DRIVING. THEN WE WILL PERFORM 3D PIC SIMULATIONS OF THE TERRESTRIAL MAGNETOTAIL WITH THE EXTENSION ALONG THE TAIL TO GLOBAL SCALES (UP TO ~10RE) THUS REDUCING THE DEPENDENCE OF THE RESULTS ON THE TYPE OF THE BOUNDARY CONDITIONS. WE WILL USE DATA FROM CLUSTER THEMIS AND GEOTAIL TO COMPARE THE RESULTS OF SIMULATIONS WITH OBSERVATIONS OF BURSTY MAGNETOTAIL PROCESSES AND TO ADJUST THE PRE-ONSET TAIL EQUILIBRIA AND SIMULATION PARAMETERS. IN ADDITION MHD SIMULATIONS WILL BE USED TO COMPLEMENT INHERENTLY LOCALIZED OBSERVATIONS IN ASSESSING THE GLOBAL PRE-ONSET TAIL STRUCTURE AND DRIVING FORCE DISTRIBUTIONS AS WELL AS TO UNDERSTAND THE RELATIVE ROLE OF IDEAL AND KINETIC INSTABILITIES. THE COMBINATION OF KINETIC AND REGIONAL MHD SIMULATIONS WILL ALSO BE USED TO FORMULATE A REDUCED KINETIC DESCRIPTION OF THE TAIL ACTIVITY MECHANISMS SUITABLE FOR GLOBAL MHD MODELS. MAGNETIC RECONNECTION BUOYANCY AND FLAPPING MOTIONS ARE UNIVERSAL PROCESSES IN SPACE PLASMAS INCLUDING MAGNETOSPHERES OF OTHER PLANETS SOLAR AND STELLAR CORONAE AS WELL AS BLACK HOLE ACCRETION DISCS. THIS STUDY WILL USE DATA FROM CURRENT SINGLE- AND MULTISPACECRAFT NASA MISSIONS TO DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE AND THE SOLAR WIND TO CHARACTERIZE KEY PROCESSES THAT OCCUR ALMOST EVERYWHERE IN SPACE PLASMAS. THUS IT DIRECTLY ADDRESSES KEY SCIENCE GOAL 2 OF THE 2013-2022 HELIOPHYSICS DECADAL SURVEY DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE IONOSPHERE AND ATMOSPHERE AND THEIR RESPONSE TO SOLAR AND TERRESTRIAL INPUTS AND GOAL 4 DISCOVER AND CHARACTERIZE FUNDAMENTAL PROCESSES THAT OCCUR BOTH WITHIN THE HELIOSPHERE AND THROUGHOUT THE UNIVERSE . IT WILL ALSO HELP IN GUIDING FUTURE NASA MISSIONS MMS AND SOLAR PROBE PLUS. IT INCLUDES RESEARCH TRAINING FOR STUDENT SUMMER INTERNS VIA THE NASA/APL SUMMER INTERN PROGRAM. $0 6/1/18 2 THE OBJECTIVE OF THIS STUDY IS TO IDENTIFY AND CHARACTERIZE THE PRIMARY PLASMA MOTIONS RESPONSIBLE FOR THE ONSET OF EXPLOSIVE MAGNETOTAIL ACTIVITY DURING SUBSTORMS AND BURSTY BULK FLOWS. THE EXPLOSIVE RELEASE OF ENERGY STORED IN THE MAGNETOTAIL IS A KEY PROCESS IN THE SOLAR WIND-MAGNETOSPHERE INTERACTION. IT DEVELOPS IN 3D OVER A BROAD RANGE OF SCALES FROM ION AND ELECTRON GYRORADII TO GLOBAL SCALES, INVOLVES BOTH MHD AND KINETIC PROCESSES AND DIFFERENT PLASMA EIGENMODES, INCLUDING MAGNETIC RECONNECTION, BUOYANCY AND FLAPPING MOTIONS. THEREFORE ITS FIRST-PRINCIPLES DESCRIPTION REQUIRES FULLY KINETIC 3D SIMULATIONS. TO BE FEASIBLE AND YIELD SIGNIFICANT RESULTS THE SIMULATIONS MUST BE CONSTRAINED BY DATA ON THE TAIL EXPLOSIONS AND ON THE TAIL STRUCTURE PRIOR TO THE EXPLOSION. IN PARTICULAR, ACCUMULATION OF MAGNETIC FLUX IN THE TAIL GIVES EITHER RECONNECTION- OR BUOYANCY-DOMINATED PICTURE OF EXPLOSIONS, WHEN IT IS SIMULATED BY CODES WITH OPEN OR CLOSED BOUNDARIES THAT DESCRIBE NEAR-EARTH OR MORE DISTANT TAIL REGIONS, RESPECTIVELY. WHICH OF THESE TWO THEORETICAL PICTURES, EACH OF WHICH IS LIMITED IN ITS SPATIAL EXTENSION TO A FEW EARTH RADII, DESCRIBES THE ACTUAL DYNAMICS OF THE GLOBAL MAGNETOTAIL DEPENDS ON THE DETAILS OF THE MAGNETIC FLUX DISTRIBUTION ALONG THE TAIL PRIOR TO THE ONSET. THUS, THE FUNDAMENTAL SCIENCE QUESTION, WHAT ARE THE PRIMARY MECHANISMS OF THE EXPLOSIVE PROCESSES IN THE MAGNETOTAIL DEPENDING ON ITS GLOBAL PRE-ONSET STRUCTURE AND SOLAR WIND DRIVING? CAN ONLY BE ANSWERED USING GLOBAL TAIL MODELS WHOSE STRUCTURE IS GUIDED BY OBSERVATIONS. IN THIS PROJECT WE PROPOSE TO USE OBSERVATIONS TO CONSTRAIN A NEW CLASS OF GLOBAL MAGNETOTAIL EQUILIBRIA, INCLUDING EFFECTS OF THE DIPOLE FIELD AND THE MAGNETIC FLUX ACCUMULATION, AND TO ASSESS THE STRENGTH OF EXTERNAL DRIVING. THEN WE WILL PERFORM 3D PIC SIMULATIONS OF THE TERRESTRIAL MAGNETOTAIL WITH THE EXTENSION ALONG THE TAIL TO GLOBAL SCALES (UP TO ~10RE) THUS REDUCING THE DEPENDENCE OF THE RESULTS ON THE TYPE OF THE BOUNDARY CONDITIONS. WE WILL USE DATA FROM CLUSTER, THEMIS AND GEOTAIL TO COMPARE THE RESULTS OF SIMULATIONS WITH OBSERVATIONS OF BURSTY MAGNETOTAIL PROCESSES AND TO ADJUST THE PRE-ONSET TAIL EQUILIBRIA AND SIMULATION PARAMETERS. IN ADDITION, MHD SIMULATIONS WILL BE USED TO COMPLEMENT INHERENTLY LOCALIZED OBSERVATIONS IN ASSESSING THE GLOBAL PRE-ONSET TAIL STRUCTURE AND DRIVING FORCE DISTRIBUTIONS AS WELL AS TO UNDERSTAND THE RELATIVE ROLE OF IDEAL AND KINETIC INSTABILITIES. THE COMBINATION OF KINETIC AND REGIONAL MHD SIMULATIONS WILL ALSO BE USED TO FORMULATE A REDUCED KINETIC DESCRIPTION OF THE TAIL ACTIVITY MECHANISMS SUITABLE FOR GLOBAL MHD MODELS. MAGNETIC RECONNECTION, BUOYANCY AND FLAPPING MOTIONS ARE UNIVERSAL PROCESSES IN SPACE PLASMAS, INCLUDING MAGNETOSPHERES OF OTHER PLANETS, SOLAR AND STELLAR CORONAE AS WELL AS BLACK HOLE ACCRETION DISCS. THIS STUDY WILL USE DATA FROM CURRENT SINGLE- AND MULTISPACECRAFT NASA MISSIONS TO DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE AND THE SOLAR WIND, TO CHARACTERIZE KEY PROCESSES THAT OCCUR ALMOST EVERYWHERE IN SPACE PLASMAS. THUS, IT DIRECTLY ADDRESSES KEY SCIENCE GOAL 2 OF THE 2013-2022 HELIOPHYSICS DECADAL SURVEY DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE, IONOSPHERE, AND ATMOSPHERE AND THEIR RESPONSE TO SOLAR AND TERRESTRIAL INPUTS AND GOAL 4 DISCOVER AND CHARACTERIZE FUNDAMENTAL PROCESSES THAT OCCUR BOTH WITHIN THE HELIOSPHERE AND THROUGHOUT THE UNIVERSE . IT WILL ALSO HELP IN GUIDING FUTURE NASA MISSIONS MMS AND SOLAR PROBE PLUS. IT INCLUDES RESEARCH TRAINING FOR STUDENT SUMMER INTERNS VIA THE NASA/APL SUMMER INTERN PROGRAM. Funding Only Action $126.6k 7/26/17