SM41D-2505
Butterfly Pitch Angle Distributions Generated at Low L Values During March 2015 Storm: Van Allen Probe ECT Observations
Thursday, 17 December 2015
Poster Hall (Moscone South)
J. F. Fennell1, Shri Kanekal2, Seth G Claudepierre3, J. Bernard Blake1, Thomas Paul O'Brien III4, Drew L Turner5, Daniel N. Baker6, Harlan E. Spence7 and Reeves Geoffrey8, (1)Aerospace Corporation Los Angeles, Los Angeles, CA, United States, (2)University of Colorado at Boulder, LASP, Boulder, CO, United States, (3)Aerospace Corporation Santa Monica, Santa Monica, CA, United States, (4)Aerospace Corporation Chantilly, Chantilly, VA, United States, (5)Aerospace Corporation El Segundo, El Segundo, CA, United States, (6)University of Colorado at Boulder, Boulder, CO, United States, (7)University of New Hampshire Main Campus, Space Science Center, Durham, NH, United States, (8)Los Alamos National Laboratory, Los Alamos, NM, United States
Abstract:
The 17 March 2015 magnetic storm was the largest storm (DST<-220 nT) in the Van Allen Probes era so far. Near the end of the main phase and during the early recovery phase of this storm the ECT MagEIS and REPT sensors observed electrons with “butterfly” type pitch angle distributions with relative minima at 90° equatorial pitch angles. The “butterfly” distributions were observed at energies that spanned the range from 32 keV to ~5 MeV. These pitch angle distributions occurred over an energy- dependent range of L-shells from L~1.5 in the inner zone out to L~3 in the slot region. In general, they occurred at the deepest L penetration point for the individual energies. We will present these observations and discuss their relationship to earlier observations and recently published simulation results.
