First Direct Observations of Propagation of Discrete Chorus Elements From the Equatorial Source to Higher Latitudes, Using the Van Allen Probes and Arase Satellites

Chris Colpitts; Yoshizumi Miyoshi; Yoshiya Kasahara; Gian Luca Delzanno; John R. Wygant; Cynthia A. Cattell; Aaron Breneman; Craig Kletzing; Greg Cunningham; Mitsuru Hikishima; Shoya Matsuda; Yuto Katoh; Jean‐Francois Ripoll; Iku Shinohara; Ayako Matsuoka

doi:10.1029/2020JA028315

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First Direct Observations of Propagation of Discrete Chorus Elements From the Equatorial Source to Higher Latitudes, Using the Van Allen Probes and Arase Satellites

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First Direct Observations of Propagation of Discrete Chorus Elements From the Equatorial Source to Higher Latitudes, Using the Van Allen Probes and Arase Satellites

Chris Colpitts, Yoshizumi Miyoshi, Yoshiya Kasahara, Gian Luca Delzanno, John R. Wygant, Cynthia A. Cattell, Aaron Breneman, Craig Kletzing, Greg Cunningham, Mitsuru Hikishima, …

Journal of geophysical research. Space physics, Vol.125(10), e2020JA028315

10/2020

DOI: 10.1029/2020JA028315

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Abstract

Whistler mode chorus waves have recently been established as the most likely candidate for scattering relativistic electrons to produce the electron microbursts observed by low altitude satellites and balloons. These waves would have to propagate from the equatorial source region to significantly higher magnetic latitude in order to scatter electrons of these relativistic energies. This theoretically proposed propagation has never been directly observed. We present the first direct observations of the same discrete rising tone chorus elements propagating from a near equatorial (Van Allen Probes) to an off‐equatorial (Arase) satellite. The chorus is observed first on the more equatorial satellite and is found to be more oblique and significantly attenuated at the off‐equatorial satellite. This is consistent with the prevailing theory of chorus propagation and with the idea that chorus must propagate from the equatorial source region to higher latitudes. Ray tracing of chorus at the observed frequencies confirms that these elements could be generated parallel to the field at the equator, and propagate through the medium unducted to Van Allen Probes A and then to Arase with the observed time delay, and have the observed obliquity and intensity at each satellite. Key Points We present the first direct observation of the same discrete rising tone chorus elements propagating from a near equatorial to an off‐equatorial satellite Chorus is observed first on the more equatorial satellite, and is more oblique and significantly attenuated at the off‐equatorial satellite Ray tracing confirms possible generation at the equator and unducted propagation with the observed time delay, obliquity, and intensity

Chorus

Propagation

Radiation Belt

Simultaneous observations

Wave

Details

Title: Subtitle: First Direct Observations of Propagation of Discrete Chorus Elements From the Equatorial Source to Higher Latitudes, Using the Van Allen Probes and Arase Satellites
Creators: Chris Colpitts - University of Minnesota
Yoshizumi Miyoshi - Nagoya University
Yoshiya Kasahara - Kanazawa University
Gian Luca Delzanno - Los Alamos National Laboratory
John R. Wygant - University of Minnesota
Cynthia A. Cattell - University of Minnesota
Aaron Breneman - University of Minnesota
Craig Kletzing - University of Iowa
Greg Cunningham - Los Alamos National Laboratory
Mitsuru Hikishima - National Sagamihara Hospital
Shoya Matsuda - ISAS/JAXA
Yuto Katoh - Tohoku University
Jean‐Francois Ripoll - UPS, CEA LMCE
Iku Shinohara - National Sagamihara Hospital
Ayako Matsuoka - Kyoto University
Resource Type: Journal article
Publication Details: Journal of geophysical research. Space physics, Vol.125(10), e2020JA028315
DOI: 10.1029/2020JA028315
ISSN: 2169-9380
eISSN: 2169-9402
Number of pages: 14
Grant note: RBSP‐EFW (922613) NASA (NAS5‐01072; 80NSSC19K0842) U.S. Department of Energy (DOE) (89233218CNA000001) International Space Science Institute's (ISSI) International Teams JSPS KAKENHI (15H05815; 15H05747; 16H06286; 20H01959; 20K14546) Los Alamos National Laboratory (LANL) (20200073DR)
Language: English
Date published: 10/2020
Academic Unit: Physics and Astronomy
Record Identifier: 9984428680502771

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