Journal article
Multiharmonic Toroidal Standing Alfvén Waves in the Midnight Sector Observed During a Geomagnetically Quiet Period
Journal of geophysical research. Space physics, Vol.125(3), e2019JA027370
03/2020
DOI: 10.1029/2019JA027370
Abstract
Excitation of toroidal mode standing Alfvén waves in the midnight sector of the inner magnetosphere in association with substorms is well documented, but studies are sparse on dayside sources for the waves. This paper reports observation of midnight toroidal waves by the Van Allen Probe B spacecraft during a geomagnetically quiet period on 12–13 May 2013. The spacecraft detected toroidal waves excited at odd harmonics below 30 mHz as it moved within the plasmasphere from urn:x-wiley:jgra:media:jgra55471:jgra55471-math-00012100 magnetic local time to urn:x-wiley:jgra:media:jgra55471:jgra55471-math-00020030 magnetic local time through midnight in the dipole urn:x-wiley:jgra:media:jgra55471:jgra55471-math-0003 range 4.2–6.1. The frequencies and the relationship between the electric and magnetic field components of the waves are consistent with theoretical toroidal waves for a reflecting ionosphere. At the time of the nightside toroidal waves, compressional waves were observed by geostationary satellites located on the dayside, and the amplitudes of both types of waves varied with the cone angle of the interplanetary magnetic field. The nightside toroidal waves were likely driven by fast mode waves that resulted from transmission of upstream ultralow frequency waves into the magnetosphere. Ground magnetometers located near the footprint of the spacecraft did not detect toroidal waves.
Details
- Title: Subtitle
- Multiharmonic Toroidal Standing Alfvén Waves in the Midnight Sector Observed During a Geomagnetically Quiet Period
- Creators
- Kazue Takahashi - The Johns Hopkins University Applied Physics Laboratory Laurel MD USAMassimo Vellante - Department of Physical and Chemical SciencesUniversity of L'Aquila L'Aquila Italy, Consorzio Area di Ricerca in Astrogeofisica L'Aquila ItalyAlfredo Del Corpo - Department of Physical and Chemical SciencesUniversity of L'Aquila L'Aquila ItalySeth G Claudepierre - Space Sciences DepartmentThe Aerospace Corporation Los Angeles CA USA, Department of Atmospheric and Oceanic SciencesUniversity of California Los Angeles CA USACraig Kletzing - Department of Physics and AstronomyUniversity of Iowa Iowa City IA USAJohn Wygant - School of Physics and AstronomyUniversity of Minnesota, Twin Cities Minneapolis MN USAKiyokazu Koga - Japan Aerospace Exploration Agency Tsukuba Japan
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.125(3), e2019JA027370
- DOI
- 10.1029/2019JA027370
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Grant note
- DOI: 10.13039/100000104, name: National Aeronautics and Space Administration, award: NNX17AD34G; DOI: 10.13039/100000179, name: Office of the Director, award: 1840970
- Language
- English
- Date published
- 03/2020
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984066336202771
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