Multi-Year Observations of Ultra-Relativistic Electrons with the Van Allen Probes Mission

Baker, Daniel

Multi-Year Observations of Ultra-Relativistic Electrons with the Van Allen Probes Mission

Monday, 5 March 2018: 08:30

Longshot and Bogey (Hotel Quinta da Marinha)

Daniel N Baker¹, Shrikanth G Kanekal², Xinlin Li³, Vaughn Hoxie¹, Allison N Jaynes⁴ and Hong Zhao⁵, (1)University of Colorado at Boulder, Boulder, CO, United States, (2)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (3)Univ Colorado at Boulder, Boulder, CO, United States, (4)University of Iowa, Iowa City, IA, United States, (5)University of Colorado Boulder, Laboratory for Atmospheric and Space Physics, Boulder, CO, United States

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Abstract:

From the launch in August 2012 to the present time, the Van Allen Probes mission has made nearly continuous measurements of the highly- and ultra-relativistic electron populations in Earth’s radiation belts. In this presentation we focus on 1-20 MeV electron measurements made by the twin Relativistic Electron-Proton Telescope (REPT) instruments that were first turned on in early September 2012. We describe the morphological features seen repeatedly in the data (3-belt structures, “impenetrable” barrier properties, radial diffusion signatures) in the context of acceleration and loss mechanisms. We especially focus on solar wind forcing of the ultra-relativistic (E ≳ 5 MeV) electron populations. We present pitch angle resolved data and energy-spectral analyses for key events. The presentation also includes animated segments portraying the mission-long time variability of the outer Van Allen belt emphasizing the remarkable dynamics of the system.