Title: Outer Radiation Belt Flux and Phase Space Density Response to Sheath Regions: Van Allen Probes and GPS Observations

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 ~ 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 calculatedmore » 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.« less

Authors:

Kalliokoski, Milla M. H.  ^[1];

• Search DOE PAGES for author "Kalliokoski, Milla M. H."
• Search DOE PAGES for ORCID "0000-0002-6445-5595"

Henderson, Michael Gerard  ^[2];

• Search DOE PAGES for author "Henderson, Michael Gerard"
• Search DOE PAGES for ORCID "0000-0003-4975-9029"

Morley, Steven Karl  ^[2];

• Search DOE PAGES for author "Morley, Steven Karl"
• Search DOE PAGES for ORCID "0000-0001-8520-0199"

Kilpua, Emilia K. J.  ^[1];

• Search DOE PAGES for author "Kilpua, Emilia K. J."
• Search DOE PAGES for ORCID "0000-0002-4489-8073"

Osmane, Adnane  ^[1];

• Search DOE PAGES for author "Osmane, Adnane"
• Search DOE PAGES for ORCID "0000-0003-2555-5953"

Olifer, Leonid  ^[3];

• Search DOE PAGES for author "Olifer, Leonid"
• Search DOE PAGES for ORCID "0000-0002-6479-2778"

Turner, Drew L.  ^[4];

• Search DOE PAGES for author "Turner, Drew L."
• Search DOE PAGES for ORCID "0000-0002-2425-7818"

Jaynes, Allison N.  ^[5];

• Search DOE PAGES for author "Jaynes, Allison N."
• Search DOE PAGES for ORCID "0000-0002-1470-4266"

George, Harriet  ^[1];

• Search DOE PAGES for author "George, Harriet"
• Search DOE PAGES for ORCID "0000-0002-3715-4623"

Hoilijoki, Sanni  ^[6];

• Search DOE PAGES for author "Hoilijoki, Sanni"
• Search DOE PAGES for ORCID "0000-0001-5709-2346"

Turc, Lucile  ^[1];

• Search DOE PAGES for author "Turc, Lucile"
• Search DOE PAGES for ORCID "0000-0002-7576-3251"

Palmroth, Minna  ^[1]

• Search DOE PAGES for author "Palmroth, Minna"
• Search DOE PAGES for ORCID "0000-0003-4857-1227"

---

+ Show Author Affiliations

1. University of Helsinki (Finland)
2. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
3. University of Alberta, Edmonton, AB (Canada)
4. Johns Hopkins University, Baltimore, MD (United States)
5. University of Iowa, Iowa City, IA (United States)
6. University of Helsinki (Finland); Finnish Meteorological Institute (FMI), Helsinki (Finland)

Publication Date:

Sat Jan 28 00:00:00 EST 2023

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program; Academy of Finland; European Research Council (ERC)

OSTI Identifier:

1974952

Report Number(s):

LA-UR-22-29034
Journal ID: ISSN 2169-9380; TRN: US2314014

Grant/Contract Number:  

89233218CNA000001; 1312390; 318913; 322544

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Geophysical Research. Space Physics

Additional Journal Information:

Journal Volume: 128; Journal Issue: 2; Journal ID: ISSN 2169-9380

Publisher:

American Geophysical Union

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS