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Inward shift of outer radiation belt electrons as a function of Dst index and the influence of the solar wind on electron injections into the slot region
Author(s) -
Zhao H.,
Li X.
Publication year - 2013
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2012ja018179
Subject(s) - van allen radiation belt , physics , solar wind , electron , geomagnetic storm , earth's magnetic field , magnetosphere , flux (metallurgy) , radiation , computational physics , atmospheric sciences , astrophysics , geophysics , plasma , magnetic field , optics , nuclear physics , materials science , quantum mechanics , metallurgy
The radial positioning of radiation belt electrons as a function of the Dst index and the controlling solar wind parameters for deep penetration of energetic electrons into the inner magnetosphere are investigated. Using 2–6 MeV electron data from the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) from January 1995 to June 2004, we examine the L location of energetic electron deepest penetration, L location of the maximum flux, and L location of the maximum flux enhancement and variation over the duration of 119 moderate and strong isolated geomagnetic storms. We find that the L location of deepest penetration, L location of the maximum flux at the end of electron injections, and L location of the maximum flux variation have strong correlations with the minimum Dst index. Although the variation and radial positioning of radiation belt electrons is clearly associated with the Dst index, their deep penetration into the slot region (2 < L < 3) is not directly correlated with the Dst index in an obvious way. It is also known that the Dst index can be accurately predicted based on solar wind parameters. Thus, the necessary and sufficient combination of solar wind conditions for the occurrence of injection events into the slot region, between L = 2–3, are also investigated. We find a total of 23 injection events at L = 2.5 from 1995 to 2004 and that when certain solar wind conditions are met, an injection event at L = 2.5 is ensured. We also find that the electron flux preconditioning is an important factor influencing electron injections at L = 2.5.