Journal article
Outer Radiation Belt Flux and Phase Space Density Response to Sheath Regions: Van Allen Probes and GPS Observations
Journal of geophysical research. Space physics, Vol.128(2), e2022JA030708
02/2023
DOI: 10.1029/2022JA030708
Abstract
Turbulent and compressed sheath regions preceding interplanetary coronal mass ejections strongly impact electron dynamics in the outer radiation belt. Changes in electron flux can occur on timescales of tens of minutes, which are unlikely to be captured by a two-satellite mission. The recently released Global Positioning System (GPS) data set generally has shorter revisit times (at L & SIM; 4-8) owing to the large number of satellites in the constellation equipped with energetic particle detectors. Investigating electron fluxes at energies from 140 keV to 4 MeV and sheaths observed in 2012-2018, we show that the flux response to sheaths on a timescale of 6 hr, previously reported from Van Allen Probes (RBSP) data, is reproduced by GPS measurements. Furthermore, GPS data enables derivation of the response on a timescale of 30 min, which further confirms that the energy and L-shell dependent changes in electron flux are associated with the impact of the sheath. Sheath-driven loss is underestimated over longer timescales as the electrons recover during the ejecta. We additionally show the response of electron phase space density (PSD), which is a key quantity in identifying non-adiabatic loss from the system and electron energization through wave-particle interactions. The PSD response is calculated from both RBSP and GPS data for the 6 hr timescale, as well as from GPS data for the 30 min timescale. The response is divided based on the geoeffectiveness of the sheaths revealing that electrons are effectively accelerated only during geoeffective sheaths, while loss commonly occurs during all sheaths.
Details
- Title: Subtitle
- Outer Radiation Belt Flux and Phase Space Density Response to Sheath Regions: Van Allen Probes and GPS Observations
- Creators
- Milla M. H. Kalliokoski - University of HelsinkiMichael G. Henderson - Los Alamos National LaboratorySteven K. Morley - Los Alamos National LaboratoryEmilia K. J. Kilpua - University of HelsinkiAdnane Osmane - Helsinki Institute of PhysicsLeonid Olifer - University of AlbertaDrew L. Turner - Johns Hopkins University Applied Physics LaboratoryAllison N. Jaynes - University of IowaHarriet George - Helsinki Institute of PhysicsSanni Hoilijoki - Helsinki Institute of PhysicsLucile Turc - Helsinki Institute of PhysicsMinna Palmroth - Helsinki Institute of Physics
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.128(2), e2022JA030708
- DOI
- 10.1029/2022JA030708
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Publisher
- Amer Geophysical Union
- Number of pages
- 17
- Grant note
- 1312390 / Finnish Centre of Excellence in Research of Sustainable Space (Academy of Finland) SolMAG 724391 / European Research Council (ERC) under the European Union; European Research Council (ERC) 312351 / Academy of Finland Los Alamos National Laboratory for the Vela Fellowship; United States Department of Energy (DOE); Los Alamos National Laboratory U.S. Department of Energy; United States Department of Energy (DOE) 682068-PRESTISSIMO / ERC under the European Union; European Research Council (ERC)
- Language
- English
- Date published
- 02/2023
- Academic Unit
- Physics and Astronomy; University College Courses
- Record Identifier
- 9984429050902771
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