THIS PROPOSED RESEARCH ADDRESSES A HIGHLY COMPELLING AND TIMELY SCIENCE TOPIC: IDENTIFYING THE CROSS-SCALE PLASMA HEATING MECHANISMS USING A RELATIVELY NEW CONCEPT OF THE CHARACTERISTIC HEATING FREQUENCY (CHF). THE COMPUTATION OF THE DISTRIBUTION AND STATISTICAL PROPERTIES OF THE CHF FOR DIFFERENT PHYSICAL MECHANISMS, SUCH AS KELVIN-HELMHOLTZ INSTABILITY (KHI) AND DRIFT-MIRROR INSTABILITY (DMI), WILL HELP UNCOVER THE PROPERTIES, E.G., TIME-SCALE AND EFFICIENCY OF PLASMA HEATING PROCESSES AT THE EARTH'S MAGNETOPAUSE. THE FOUR-SPACECRAFT MEASUREMENTS FROM THE MAGNETOSPHERIC MULTISCALE (MMS) MISSION WILL BE USED TO ADDRESS THE FOLLOWING SCIENTIFIC QUESTIONS: 1. WHAT ARE THE CHF DISTRIBUTIONS DURING EACH PHYSICAL PROCESS (KELVIN-HELMHOLTZ INSTABILITY, DRIFT MIRROR INSTABILITY, ETC.)? HOW ARE THEY DIFFERENT DURING DIFFERENT MECHANISMS? 2. HOW BEHAVES THE CHF DISTRIBUTION DURING THE CROSSING OF THE ION-SCALE CURRENT SHEETS DURING A KHI EVENT? 3. ANOTHER FITTING METHOD FOR THE KAPPA DISTRIBUTION WILL BE INVOLVED. WHAT IS THE DIFFERENCE COMPARED TO THE ORIGINAL DISTRIBUTION FITTING METHOD?