Journal article
Multipoint observations of compressional Pc5 pulsations in the dayside magnetosphere and corresponding particle signatures
Annales geophysicae (1988), Vol.38(6), pp.1267-1281
12/21/2020
DOI: 10.5194/angeo-38-1267-2020
Abstract
We use Van Allen Probes (Radiation Belt Storm Probes A and B, henceforth RBSP-A and RBSP-B) and GOES-13 and GOES-15 (henceforth G-13 and G-15) multipoint magnetic field, electric field, plasma, and energetic particle observations to study the spatial, temporal, and spectral characteristics of compressional Pc5 pulsations observed during the recovery phase of a strong geomagnetic storm on 1 January 2016. From similar to 19:00 to 23:02 UT, successive magnetospheric compressions enhanced the peak-to-peak amplitudes of Pc5 waves with 4.5-6.0 mHz frequencies from 0-2 to 10-15 nT at both RBSP-A and RBSP-B, particularly in the prenoon magnetosphere. Poloidal Pc4 pulsations with frequencies of similar to 22-29 mHz were present in the radial Bx component. The frequencies of these Pc4 pulsations diminished with increasing radial distance, as expected for resonant Alfven waves standing along field lines. The GOES spacecraft observed Pc5 pulsations with similar frequencies to those seen by the RBSP but Pc4 pulsations with lower frequencies.
Both RBSP-A and RBSP-B observed frequency doubling in the compressional component of the magnetic field during the Pc5 waves, indicating a meridional sloshing of the equatorial node over a combined range in Z(SM) from 0.25 to -0.08 Re, suggesting that the amplitude of this meridional oscillation was similar to 0.16 Re about an equatorial node whose mean position was near Z(SM) = similar to 0.08 Re. RBSP-A and RBSP-B HOPE (Helium Oxygen Proton Electron) and MagEIS (Magnetic Electron Ion Spectrometer) observations provide the first evidence for a corresponding frequency doubling in the plasma density and the flux of energetic electrons, respectively. Energetic electron fluxes oscillated out of phase with the magnetic field strength with no phase shift at any energy. In the absence of any significant solar wind trigger or phase shift with energy, we interpret the compressional Pc5 pulsations in terms of the mirror-mode instability.
Details
- Title: Subtitle
- Multipoint observations of compressional Pc5 pulsations in the dayside magnetosphere and corresponding particle signatures
- Creators
- Galina Korotova - University of Maryland, College ParkDavid Sibeck - Goddard Space Flight CenterMark Engebretson - Augsburg UniversityMichael Balikhin - University of SheffieldScott Thaller - University of Colorado BoulderCraig Kletzing - University of IowaHarlan Spence - University of New HampshireRobert Redmon - National Oceanic and Atmospheric Administration
- Resource Type
- Journal article
- Publication Details
- Annales geophysicae (1988), Vol.38(6), pp.1267-1281
- DOI
- 10.5194/angeo-38-1267-2020
- ISSN
- 0992-7689
- eISSN
- 1432-0576
- Publisher
- Copernicus Gesellschaft Mbh
- Number of pages
- 15
- Grant note
- 80NSSC19K0440; NAS5-01072 / NASA; National Aeronautics & Space Administration (NASA) UMN 922613 / APL; Australian Pork Limited WBS 605745.04.01 / GSFC ST/R000697/1 / STFC; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) ST/R000697/1 / UK Science and Technology Facilities Council (STFC); UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC)
- Language
- English
- Date published
- 12/21/2020
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984428787702771
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