THE PI YUKITOSHI NISHIMURA MOVED FROM THE ORIGINAL INSTITUTION (UCLA) TO THE NEW INSTITUTION (BOSTON UNIVERSITY) IN SEPTEMBER 2016. THEREFORE THE REMAINING TASKS OF THIS PROPOSED PROJECT DURING 04/16/2016 04/15/2018 WILL BE PRIMARILY PERFORMED AT BOSTON UNIVERSITY WITH THE ORIGINAL POSTDOCTORAL SCHOLAR (YING ZOU) ALSO RELOCATING TO BOSTON UNIVERSITY COLLABORATING WITH THE ORIGINAL CO-IS WHOSE APPOINTMENT CONTINUES AT UCLA. THE PI REQUESTS TO TRANSFER THIS GRANT FROM UCLA TO BOSTON UNIVERSITY. THE OVERARCHING GOAL OF THIS PROPOSED STUDY IS TO DETERMINE THE PROPERTIES OF WAVES BEFORE AND DURING SUBSTORM AURORAL ONSET AND THE ROLE OF KINETIC INSTABILITY IN TRIGGERING THOSE WAVES WHICH IS A FUNDAMENTAL ISSUE FOR UNDERSTANDING THE PLASMA SHEET INSTABILITY THAT TRIGGERS SUBSTORM EXPANSION PHASE ONSET. THREE SPECIFIC SCIENCE TASKS ARE: (1) DETERMINE PROPERTIES OF PRE-ONSET WAVES AND THEIR CONNECTION TO ONSET WAVES (DATA ANALYSIS) (2) DETERMINE PROPERTIES OF ONSET WAVES (DATA ANALYSIS) (3) DETERMINE THE ROLE OF KINETIC BALLOONING INSTABILITY FOR DRIVING PRE-ONSET AND ONSET WAVES (DATA-MODEL COMPARISON) THIS PROPOSED STUDY AIMS TO REVEAL FUNDAMENTAL PHYSICAL PROCESSES OF SUBSTORM ONSET WHICH IS A CRITICAL ISSUE IN MAGNETOSPHERE-IONOSPHERE COUPLING AND MAGNETOTAIL PLASMA PHYSICS. THUS THIS STUDY ADDRESSES #8 OF THE PRIMARY SCIENCE AREA OF THE H-SR PROGRAM: MAGNETOSPHEREIONOSPHERE COUPLING PHYSICS AND MAGNETOTAIL. ALSO THIS STUDY OF SUBSTORM ONSET DIRECTLY ADDRESSES HELIOPHYSICS DECADAL SURVEY GOAL #4: DISCOVER AND CHARACTERIZE FUNDAMENTAL PROCESSES THAT OCCUR BOTH WITHIN THE HELIOSPHERE AND THROUGHOUT THE UNIVERSE AND THE COORDINATED STUDY OF SUBSTORM ONSET IN THE MAGNETOSPHERE AND IONOSPHERE WILL ADDRESS THE M-I COUPLING PORTION OF THE HELIOPHYSICS DECADAL SURVEY GOAL #2: DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE IONOSPHERE AND ATMOSPHERE AND THEIR RESPONSE TO SOLAR AND TERRESTRIAL INPUTS.