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Title: The evolution of ring current ion energy density and energy content during geomagnetic storms based on Van Allen Probes measurements

Enabled by the comprehensive measurements from the Magnetic Electron Ion Spectrometer (MagEIS), Helium Oxygen Proton Electron mass spectrometer (HOPE), and Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instruments onboard Van Allen Probes in the heart of the radiation belt, the relative contributions of ions with different energies and species to the ring current energy density and their dependence on the phases of geomagnetic storms are quantified. The results show that lower energy (<50 keV) protons enhance much more often and also decay much faster than higher-energy protons. During the storm main phase, ions with energies <50 keV contribute more significantly to the ring current than those with higher energies; while the higher-energy protons dominate during the recovery phase and quiet times. The enhancements of higher-energy proton fluxes as well as energy content generally occur later than those of lower energy protons, which could be due to the inward radial diffusion. For the 29 March 2013 storm we investigated in detail that the contribution from O + is ~25% of the ring current energy content during the main phase and the majority of that comes from <50 keV O +. This indicates that even during moderate geomagnetic storms the ionospheremore » is still an important contributor to the ring current ions. Using the Dessler-Parker-Sckopke relation, the contributions of ring current particles to the magnetic field depression during this geomagnetic storm are also calculated. In conclusion, the results show that the measured ring current ions contribute about half of the Dst depression.« less
 [1] ;  [1] ;  [2] ;  [3] ;  [3] ; ORCiD logo [4] ;  [4] ;  [4] ; ORCiD logo [4] ; ORCiD logo [4] ;  [5] ;  [6] ;  [7] ; ORCiD logo [8]
  1. Univ. of Colorado, Boulder, CO (United States). Lab. for Atmospheric and Space Physics; Univ. of Colorado, Boulder, CO (United States). Dept. of Aerospace Engineering Sciences
  2. Univ. of Colorado, Boulder, CO (United States). Lab. for Atmospheric and Space Physics
  3. Aerospace Corporation, Los Angeles, CA (United States). Space Sciences Dept.
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  5. Univ. of New Hampshire, Durham, NH (United States). Inst. for the Study of Earth, Oceans, and Space
  6. Johns Hopkins Univ., Laurel, MD (United States). Applied Physics Lab., Space Dept.
  7. New Jersey Inst. of Technology, Newark, NJ (United States). Center for Solar-Terrestrial Research
  8. Univ. of Colorado, Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences; National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). National Centers for Environmental Information
Publication Date:
Report Number(s):
Journal ID: ISSN 2169-9380; TRN: US1703000
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Space Physics
Additional Journal Information:
Journal Volume: 120; Journal Issue: 9; Journal ID: ISSN 2169-9380
American Geophysical Union
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
National Aeronautic and Space Administration (NASA)
Country of Publication:
United States
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 58 GEOSCIENCES; Heliospheric and Magnetospheric Physics; ring current ions; ring current energy content; geomagnetic storms; the DPS relation; the Dst index; Van Allen Probes
OSTI Identifier: