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SCIENCE GOALS&OBJECTIVES OUR FOCUSED SCIENCE OBJECTIVE IS TO DETERMINE THE RELATIVE IMPORTANCE OF EXTERNAL SOLAR WIND CONDITIONS AND WAVE-PARTICLE INTERACTIONS IN HEATING THE PLASMA AND ACCELERATING PARTICLES AT HIGH MACH NUMBER QUASI-PERPENDICULAR PORTIONS OF THE EARTH'S BOW SHOCK. TO ACHIEVE THIS OBJECTIVE WE WILL ANSWER THE FOLLOWING THREE SCIENCE QUESTIONS: 1) HOW DO EXTERNAL FACTORS (E.G. SOLAR WIND CONDITIONS PLASMA BETA DENSITY&TEMPERATURE) DETERMINE THE BOW SHOCK'S MACRO-SCALE STRUCTURE AND AFFECT THE ASSOCIATED ION AND ELECTRON VELOCITY DISTRIBUTION FUNCTIONS 2) HOW ARE PROPERTIES OF AMBIENT TURBULENCE PLASMA INSTABILITIES AND LOCALLY-GENERATED WAVES RELATED TO THE EVOLUTION OF ELECTRON AND ION DISTRIBUTIONS UPSTREAM AND DOWNSTREAM OF THE SHOCK 3) WHAT PORTIONS OF THE ION AND ELECTRON POPULATIONS IN VELOCITY SPACE PARTICIPATE IN GETTING HEATED AND ACCELERATED AT THE BOW SHOCK? SCIENTIFIC IMPORTANCE / SIGNIFICANCE COLLISIONLESS SHOCKS ARE A MAJOR PRODUCER OF SUPRATHERMAL AND ENERGETIC PARTICLES IN SPACE AND ASTROPHYSICAL PLASMA ENVIRONMENTS. THEORETICAL STUDIES COMBINED WITH IN-SITU OBSERVATIONS DURING THE SPACE AGE HAVE SIGNIFICANTLY ADVANCED OUR UNDERSTANDING OF THE PHYSICAL PROCESSES ASSOCIATED WITH SUCH SHOCKS. HOWEVER IT IS STILL POORLY UNDERSTOOD EXACTLY HOW COLLISIONLESS SHOCKS ARE FORMED THE MANNER IN WHICH THEY EVOLVE AND DISSIPATE THEIR ENERGY AND THE PHYSICAL MECHANISMS BY WHICH THEY HEAT AND ACCELERATE THE LOCAL PLASMA. METHODOLOGY: DATA ANALYSIS WE ANSWER THE ABOVE SCIENCE QUESTIONS THROUGH A SYSTEMATIC ANALYSIS OF HIGH TIME RESOLUTION BURST DATA FROM NASA'S MAGNETOSPHERIC MULTISCALE (MMS) MISSION DURING MULTIPLE BOW SHOCK CROSSINGS. WE CHARACTERIZE THE EVOLUTION OF PARALLEL AND PERPENDICULAR TEMPERATURES AND THE VELOCITY DISTRIBUTION FUNCTIONS OF IONS AND ELECTRONS IN THE UPSTREAM AND DOWNSTREAM REGIONS. WE USE THE HIGHEST-TIME-RESOLUTION ELECTRIC AND MAGNETIC FIELD DATA TO DERIVE THE POWER SPECTRAL DENSITIES AND POLARIZATION CHARACTERISTICS TO IDENTIFY THE NATURE AND PROPERTIES OF TURBULENCE INSTABILITIES WAVES (AMBIENT AND SELF-EXCITED) ASSOCIATED WITH QUASI-PERPENDICULAR BOW SHOCK CROSSINGS. WE USE A NOVEL FIELD-PARTICLE CORRELATION ANALYSES TECHNIQUE TO PERFORM CROSS-SENSOR ANALYSES AND IDENTIFY KEY PARAMETERS THAT ARE ASSOCIATED WITH THE ION AND ELECTRON POPULATIONS IN VELOCITY SPACE THAT PARTICIPATE IN DISSIPATION AND ENERGIZATION AT EACH SHOCK CROSSING. FINALLY WE USE A STATE-OF-THE-ART GLOBAL ELECTROMAGNETIC HYBRID (KINETIC IONS AND FLUID ELECTRONS) SIMULATIONS TO MODEL THE SHOCK STRUCTURE AND STUDY WAVE-PARTICLE BEHAVIOR IN ~2-3 CASE STUDIES. MISSION DATA LAUNCHED IN MARCH 2015 MMS HAS FOUR SPACECRAFT SEPARATED BETWEEN ~10-40 KM AND EQUIPPED WITH IDENTICAL STATE-OF-THE-ART INSTRUMENTS THAT ACQUIRE MAGNETIC AND ELECTRIC FIELD PLASMA WAVE AND PARTICLE DATA AT UNPRECEDENTED TEMPORAL RESOLUTION TO STUDY THE FUNDAMENTAL PHYSICS OF MAGNETIC RECONNECTION IN THE EARTH'S MAGNETOSPHERE. SERENDIPITOUSLY DURING PHASE 1A FROM OCTOBER 2015 THROUGH DECEMBER 31 2015 MMS ALSO ENCOUNTERED AND CROSSED THE EARTH'S BOW SHOCK MORE THAN ~400 TIMES AND MORE IMPORTANTLY ACQUIRED HIGHEST TIME RESOLUTION BURST DATA DURING>230 SUCH CROSSINGS. RELEVANCE TO MMS AND DECADAL SURVEY THE PROPOSED RESEARCH IS HIGHLY RELEVANT TO THE MMS-GI PROGRAM AS IT USES THE HIGHEST CADENCE OR TIME RESOLUTION MMS BURST DATA DURING NUMEROUS BOW SHOCK CROSSINGS TO ADDRESS A FUNDAMENTAL SCIENCE QUESTION THAT IS CRITICAL FOR NASA'S HELIOPHYSICS DIVISION - HOW DO COLLISONLESS SHOCKS HEAT THE LOCAL PLASMA AND ACCELERATE THE PARTICLES OUR PROPOSED RESEARCH ALSO ADDRESSES TWO OF THE 2012 SOLAR AND SPACE PHYSICS DECADAL SURVEY GOALS NAMELY DS2: DETERMINE THE DYNAMICS AND COUPLING OF EARTH'S MAGNETOSPHERE IONOSPHERE AND ATMOSPHERE AND THEIR RESPONSE TO SOLAR AND TERRESTRIAL INPUTS. DS4: DISCOVER AND CHARACTERIZE FUNDAMENTAL PROCESSES THAT OCCUR BOTH WITHIN THE HELIOSPHERE AND THROUGHOUT THE UNIVERSE.

$569,192FY2020National Aeronautics and Space AdministrationNASA

Southwest Research Institute, San Antonio TX

Investigators

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