High-resolution in situ observations of electron precipitation-causing EMIC waves

• Published in: Geophysical research letters Vol. 42; no. 22; pp. 9633 - 9641
• Main Authors: Rodger, Craig J., Hendry, Aaron T., Clilverd, Mark A., Kletzing, Craig A., Brundell, James B., Reeves, Geoffrey D.
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 28-11-2015; John Wiley & Sons, Inc; American Geophysical Union
• Subjects: Electron precipitation; EMIC waves; energetic electron precipitation; Flux; GEOSCIENCES; Ground-based observation; Hydrologic data; Jupiter; Outer radiation belt; Pitch angle; Precipitation (meteorology); radiation belt electrons; Satellite observation; Wave power; wave-particle interactions
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2015GL066581

Electromagnetic ion cyclotron (EMIC) waves are thought to be important drivers of energetic electron losses from the outer radiation belt through precipitation into the atmosphere. While the theoretical possibility of pitch angle scattering‐driven losses from these waves has been recognized for more than four decades, there have been limited experimental precipitation observations to support this concept. We have combined satellite‐based observations of the characteristics of EMIC waves, with satellite and ground‐based observations of the EMIC‐induced electron precipitation. In a detailed case study, supplemented by an additional four examples, we are able to constrain for the first time the location, size, and energy range of EMIC‐induced electron precipitation inferred from coincident precipitation data and relate them to the EMIC wave frequency, wave power, and ion band of the wave as measured in situ by the Van Allen Probes. These observations will better constrain modeling into the importance of EMIC wave‐particle interactions.
Key Points
EMIC waves are thought to be highly important drivers of electron loss from the outer radiation belt
To date, there are few experimental examples of precipitation‐causing EMIC events
Simultaneous in situ EMIC wave, plasma, and precipitation flux measurements made for the first time