Van Allen Probes, NOAA, and Ground Observations of an Intense Pc 1 Wave Event Extending 12 Hours in MLT

Mark J Engebretson, Augsburg University, Physics, Minneapolis, United States, Jennifer L Posch, Augsburg University, Minneapolis, MN, United States, John R Wygant, University of Minnesota Twin Cities, Minneapolis, MN, United States, Craig Kletzing, University of Iowa, Physics and Astronomy, Iowa City, United States, Marc Lessard, University of New Hampshire Main Campus, Durham, NH, United States, Richard Bertram Horne, NERC British Antarctic Survey, Cambridge, United Kingdom, Geoffrey D Reeves, Los Alamos National Laboratory, Los Alamos, United States, Matina Gkioulidou, JHU/APL, Laurel, United States, Joseph Fennell, Aerospace Corporation, Los Angeles, CA, United States, Kjellmar Oksavik, University of Bergen, Department of Physics and Technology, Bergen, Norway and Raita Tero, University of Oulu, Sodankyla Geophysical Observatory, Sodankyla, Finland
Abstract:
On February 23, 2014 a Pc 1 wave event extending 8 hours in UT and 12 hours in MLT was observed at Halley, Antarctica and Ivalo, Finland in the dawn sector, and by both Van Allen Probes spacecraft from late morning through local noon. The wave activity was stimulated by a gradual 4-hour rise and subsequent sharp increases in solar wind pressure. Intense hydrogen band, linearly polarized Pc 1 wave activity (up to 25 nT p-p) with very similar time variations also appeared for over 4 hours at both Van Allen Probes, located ~8 and ~9 hours east of Halley. Waves appeared when these spacecraft were outside the plasmapause, with densities ~5-20 cm-3. Ten passes of NOAA-POES and METOP satellites near the northern hemisphere footpoint of the Van Allen Probes (over Siberia) show the presence of 30-80 keV subauroral proton precipitation. This is the longest-duration and most intense Pc1 event we have yet observed with the Van Allen Probes. The combination of its duration, intensity, and large local time extent (from before 02 to nearly 14 hours MLT) suggests that it might have a significant effect on the ring current, and possibly even electrons in the outer radiation belt.
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