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| Titel |
Magnetohydrodynamic modeling of three Van Allen Probes storms in 2012 and 2013 |
| VerfasserIn |
J. Paral, M. K. Hudson, B. T. Kress, M. J. Wiltberger, J. R. Wygant, H. J. Singer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 33, no. 8 ; Nr. 33, no. 8 (2015-08-20), S.1037-1050 |
| Datensatznummer |
250121238
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| Publikation (Nr.) |
 copernicus.org/angeo-33-1037-2015.pdf |
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| Zusammenfassung |
| Coronal mass ejection (CME)-shock compression of the dayside magnetopause has been observed to cause
both prompt enhancement of radiation belt electron flux due to inward radial
transport of electrons conserving their first adiabatic invariant and prompt
losses which at times entirely eliminate the outer zone. Recent numerical
studies suggest that enhanced ultra-low frequency (ULF) wave activity is
necessary to explain electron losses deeper inside the magnetosphere than
magnetopause incursion following CME-shock arrival. A combination of radial
transport and magnetopause shadowing can account for losses observed at
radial distances into L = 4.5, well within the computed magnetopause location.
We compare ULF wave power from the Electric Field and Waves (EFW) electric field instrument on the Van
Allen Probes for the 8 October 2013 storm with ULF wave power simulated using
the Lyon–Fedder–Mobarry (LFM) global magnetohydrodynamic (MHD) magnetospheric simulation code
coupled to the Rice Convection Model (RCM). Two other storms with strong
magnetopause compression, 8–9 October 2012 and 17–18 March 2013, are also
examined. We show that the global MHD model captures the azimuthal
magnetosonic impulse propagation speed and amplitude observed by the Van
Allen Probes which is responsible for prompt acceleration at MeV energies
reported for the 8 October 2013 storm. The simulation also captures the ULF
wave power in the azimuthal component of the electric field, responsible for
acceleration and radial transport of electrons, at frequencies comparable to
the electron drift period. This electric field impulse has been shown to
explain observations in related studies (Foster et al., 2015) of electron
acceleration and drift phase bunching by the Energetic Particle,
Composition, and Thermal Plasma Suite (ECT) instrument on the Van Allen Probes. |
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