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Title: Driving ionospheric outflows and magnetospheric O + energy density with Alfvén waves

We show how dispersive Alfvén waves observed in the inner magnetosphere during geomagnetic storms can extract O + ions from the topside ionosphere and accelerate these ions to energies exceeding 50 keV in the equatorial plane. This occurs through wave trapping, a variant of “shock” surfing, and stochastic ion acceleration. These processes in combination with the mirror force drive field-aligned beams of outflowing ionospheric ions into the equatorial plane that evolve to provide energetic O + distributions trapped near the equator. These waves also accelerate preexisting/injected ion populations on the same field lines. We show that the action of dispersive Alfvén waves over several minutes may drive order of magnitude increases in O + ion pressure to make substantial contributions to magnetospheric ion energy density. These wave accelerated ions will enhance the ring current and play a role in the storm time evolution of the magnetosphere.
Authors:
 [1] ;  [2] ; ORCiD logo [3] ;  [4]
  1. Univ. of California, Berkeley, CA (United States). Space Sciences Lab.; Univ. of Sydney, NSW (Australia). School of Physics
  2. Univ. of California, Berkeley, CA (United States). Space Sciences Lab.
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); New Mexico Consortium, Los Alamos, NM (United States). Space Sciences Division
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
LA-UR-16-23143
Journal ID: ISSN 0094-8276; TRN: US1702878
Grant/Contract Number:
AC52-06NA25396; NNX11AD78G; NNX15AF57G; NNX16AG69G; NAS5-01072; FT110100316
Type:
Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 43; Journal Issue: 10; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
National Aeronautic and Space Administration (NASA); USDOE
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; Heliospheric and Magnetospheric Physics; Alfvén waves; ion acceleration; ring current; ionosphere; ionospheric outflow
OSTI Identifier:
1402612

Chaston, C. C., Bonnell, J. W., Reeves, Geoffrey D., and Skoug, R. M.. Driving ionospheric outflows and magnetospheric O+ energy density with Alfvén waves. United States: N. p., Web. doi:10.1002/2016GL069008.
Chaston, C. C., Bonnell, J. W., Reeves, Geoffrey D., & Skoug, R. M.. Driving ionospheric outflows and magnetospheric O+ energy density with Alfvén waves. United States. doi:10.1002/2016GL069008.
Chaston, C. C., Bonnell, J. W., Reeves, Geoffrey D., and Skoug, R. M.. 2016. "Driving ionospheric outflows and magnetospheric O+ energy density with Alfvén waves". United States. doi:10.1002/2016GL069008. https://www.osti.gov/servlets/purl/1402612.
@article{osti_1402612,
title = {Driving ionospheric outflows and magnetospheric O+ energy density with Alfvén waves},
author = {Chaston, C. C. and Bonnell, J. W. and Reeves, Geoffrey D. and Skoug, R. M.},
abstractNote = {We show how dispersive Alfvén waves observed in the inner magnetosphere during geomagnetic storms can extract O+ ions from the topside ionosphere and accelerate these ions to energies exceeding 50 keV in the equatorial plane. This occurs through wave trapping, a variant of “shock” surfing, and stochastic ion acceleration. These processes in combination with the mirror force drive field-aligned beams of outflowing ionospheric ions into the equatorial plane that evolve to provide energetic O+ distributions trapped near the equator. These waves also accelerate preexisting/injected ion populations on the same field lines. We show that the action of dispersive Alfvén waves over several minutes may drive order of magnitude increases in O+ ion pressure to make substantial contributions to magnetospheric ion energy density. These wave accelerated ions will enhance the ring current and play a role in the storm time evolution of the magnetosphere.},
doi = {10.1002/2016GL069008},
journal = {Geophysical Research Letters},
number = 10,
volume = 43,
place = {United States},
year = {2016},
month = {5}
}