Van Allen Probes observations of electron response to the 2016 October 12-13 IP shock and magnetic cloud

Tuesday, 6 March 2018
Lakehouse (Hotel Quinta da Marinha)
Ashley Diemer Jones Greeley, Catholic University of America, physics, Washington, DC, United States, Shrikanth G Kanekal, Heliophysics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States, Daniel N Baker, LASP, University of Colorado at Boulder, Boulder, CO, United States, Joseph F. Fennell, Aerospace Corporation, Los Angeles, CA, United States and David G Sibeck, NASA Goddard Space Flight Center, Greenbelt, MD, United States
Abstract:
Late on October 12, 2016, an interplanetary shock (IP) was measured by SOHO (Solar and Heliospheric Observatory), characterized by a sharp jump in the solar wind speed (350 to 425 km/s), proton density (dn/n>3), interplanetary magnetic field (IMF) B (dB/B>4), and thermal speed (15 to 35 km/s) at 21:25. The shock hit the Earth at 22:15. The coronal mass ejection following the shock contained a magnetic cloud with a strongly enhanced IMF, B > 20 nT, as seen by ACE (Advanced Composition Explorer) and Wind. This event caused a moderate geomagnetic storm (minimum Dst ~-100 nT) and a response by energetic particles in the radiation belts, as observed by the Van Allen Probes. We study this event using both the Relativistic Electron and Proton Telescope (REPT) and the Magnetic Electron and Ion Sensors (MagEIS) on the Van Allen Probes, which cover a wide range of electron energies, on the scale of tens of keV to tens of MeV and provide detailed pitch angle measurements. Probe A was located around L=3 and on the dawn side, and probe B was L<2 on the dusk side and are both able to see the 90° dropouts that occur during the main phase of the storm. We analyze the spectra and pitch angle distributions as a function of time, and relate their evolution to the properties of the magnetic cloud and shock.
<< Previous Abstract | Next Abstract >>