Outer radiation belt and inner magnetospheric response to sheath regions of coronal mass ejections: A statistical analysis
- 1Department of Physics, University of Helsinki, Helsinki, Finland
- 2Space Sciences Department, The Aerospace Corporation, El Segundo, California, USA
- 3Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, USA
- 4Finnish Meteorological Institute, Helsinki, Finland
- 1Department of Physics, University of Helsinki, Helsinki, Finland
- 2Space Sciences Department, The Aerospace Corporation, El Segundo, California, USA
- 3Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, USA
- 4Finnish Meteorological Institute, Helsinki, Finland
Abstract. The energetic electron content in the Van Allen radiation belts surrounding the Earth can vary dramatically on several timescales, and these strong electron fluxes present a hazard for spacecraft traversing the belts. The belt response to solar wind driving is yet largely unpredictable and especially the direct response to specific large-scale heliospheric structures has not been considered previously. We investigate the immediate response of electron fluxes in the outer belt to driving by sheath regions preceding interplanetary coronal mass ejections and the associated wave activity in the inner magnetosphere. We consider events from 2012 to 2018 in the Van Allen Probes era to employ the energy and radial distance resolved electron flux observations of the twin spacecraft mission. We perform a statistical study of the events using superposed epoch analysis, where the sheaths are superposed separately from the ejecta and resampled to the same average duration. Our results show that wave power of ultra-low frequency Pc5 and electromagnetic ion cyclotron waves, as measured by a geostationary GOES satellite, is higher during the sheaths than during the ejecta. However, the level of chorus wave power remains approximately the same, despite on average stronger ring current enhancements during the ejecta. Electron flux enhancements are common at low energies (< 1 MeV) throughout the outer belt (L = 3–6), whereas depletion occurs predominantly at high energies for high L-shells (L > 4). Distinctively, depletion extends to lower energies at larger distances. We suggest that this L-shell and energy dependent depletion results from magnetopause shadowing dominating the losses at large distances, while wave-particle interactions dominate closer to the Earth. We also show that non-geoeffective sheaths cause significant changes in the outer belt electron fluxes.
-
Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
-
Preprint
(7288 KB)
-
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
Journal article(s) based on this preprint
Milla M. H. Kalliokoski et al.
Interactive discussion
-
RC1: 'Review of the manuscript angeo-2019-150 with title "Outer radiation belt and inner magnetospheric response to sheath regions of coronal mass ejections: A statistical analysis"', Anonymous Referee #1, 28 Nov 2019
- AC1: 'Response to Referee #1', Milla Kalliokoski, 25 Jan 2020
-
RC2: 'Comments', Anonymous Referee #2, 30 Nov 2019
- AC2: 'Response to Referee #2', Milla Kalliokoski, 25 Jan 2020
Peer-review completion
Interactive discussion
-
RC1: 'Review of the manuscript angeo-2019-150 with title "Outer radiation belt and inner magnetospheric response to sheath regions of coronal mass ejections: A statistical analysis"', Anonymous Referee #1, 28 Nov 2019
- AC1: 'Response to Referee #1', Milla Kalliokoski, 25 Jan 2020
-
RC2: 'Comments', Anonymous Referee #2, 30 Nov 2019
- AC2: 'Response to Referee #2', Milla Kalliokoski, 25 Jan 2020
Peer-review completion
Journal article(s) based on this preprint
Milla M. H. Kalliokoski et al.
Milla M. H. Kalliokoski et al.
Viewed
HTML | XML | Total | BibTeX | EndNote | |
---|---|---|---|---|---|
223 | 142 | 7 | 372 | 6 | 16 |
- HTML: 223
- PDF: 142
- XML: 7
- Total: 372
- BibTeX: 6
- EndNote: 16
Viewed (geographical distribution)
Country | # | Views | % |
---|
Total: | 0 |
HTML: | 0 |
PDF: | 0 |
XML: | 0 |
- 1
Cited
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(7288 KB) - Metadata XML