SM009-01
Ultra-Low Frequency waves and their direct role in energetic particle precipitation
Monday, 7 December 2020: 17:30
Virtual
Jonathan Rae1, Kyle R Murphy2, Andrew Inglis3, Clare Watt4, Alexa Jean Halford5, Alexander W Degeling6, Mark A. Clilverd7, Craig J Rodger8 and Quanqi Shi6, (1)Northumbria University, Newcastle, United Kingdom, (2)University of Maryland College Park, College Park, United States, (3)Catholic University of America, Washington, DC, United States, (4)Northumbria University, Newcastle-upon-Tyne, United Kingdom, (5)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (6)Shandong University at Weihai, Weihai, China, (7)British Antarctic Survey, Cambridge, United Kingdom, (8)University of Otago, Department of Physics, Dunedin, New Zealand
Abstract:
In this study we present a discussion of the loss mechanisms for energetic electrons related to ULF waves. We present evidence for electron loss through precipitation into the ionosphere due to a direct modulation of the loss cone via radially and azimuthally localized compressional ULF waves, which acts in tandem with traditional wave-particle interaction mechanisms.
We further investigate this mechanism using a novel analysis to statistically investigate the relationship between ULF wave mode and their resultant ULF-modulated ionospheric precipitation. We find strong relationships between ULF-modulated precipitation signatures with both poloidal-mode and compressional-mode ULF waves and find no relationship between the presence of toroidal-mode ULF waves and ULF-modulated precipitation. Moreover, we find that these ULF waves with a compressional component exist at all magnetic local times, demonstrating that these signatures are independent of other wave-particle action on energetic electrons.
These results are strong evidence that ULF waves can provide a direct effect in encouraging electrons close to the nominal loss cone to precipitate, that act in addition to gyroresonant wave-particle interactions.
