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Modeling the loss of inner belt protons by magnetic field line curvature scattering


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dc.contributorKaijun Liuen_US
dc.creatorTu, Weichao
dc.creatorCowee, M. M.
dc.creatorLiu, Kaijun
dc.date.accessioned2020-06-05T19:57:05Z
dc.date.available2020-06-05T19:57:05Z
dc.date.created2014-07
dc.identifier10.1002/2014JA019864en_US
dc.identifier.urihttps://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014JA019864en_US
dc.identifier.urihttp://hdl.handle.net/11200/49863
dc.description.abstractThe sudden loss of energetic protons in the inner radiation belt has been observed during geomagnetic storms. It is hypothesized that this sudden loss occurs because of changes in the geomagnetic field configuration which lead to a breakdown of the first adiabatic invariant, mu, in a process called magnetic field line curvature scattering or mu scattering. Comparison of observations to various analytic model predictions for mu scattering induced loss has, however, yielded discrepancies. To better understand how well the analytic models predict the proton loss, test particle simulations are carried out for various magnetic field configurations. Although our simulation results agree well with the analytic models for single-scattering events, the results after cumulative mu scattering can show significant disagreement with the theoretical predictions based on analytic models. In particular, we find the assumption that protons with predicted initial delta mu/mu 0.01 or epsilon > 0.1 are ultimately lost overestimates the proton loss. Based on the test particle simulation results, we develop a new empirical model, called the "epsilon-onset" model, to predict the minimum value of e at which all protons of a given pitch angle and energy can be assumed to be lost due to mu scattering. By applying our epsilon-onset model as the variable cutoff condition between trapping and detrapping, we obtain very good agreement between theoretical predictions and the simulation results for a range of Kp, suggesting that the epsilon-onset model can potentially serve as an easy-to-use and more reliable predictor of inner belt proton loss due to mu scattering than the previously used fixed-valued cutoff conditions.en_US
dc.formatPDFen_US
dc.publisherAMER GEOPHYSICAL UNIONen_US
dc.relation.ispartofJOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICSen_US
dc.relation.ispartofseries2169-9380en_US
dc.subjectPITCH ANGLE DIFFUSION; RADIATION BELT; PLASMA SHEET; PARTICLE; MAGNETOTAILen_US
dc.titleModeling the loss of inner belt protons by magnetic field line curvature scatteringen_US
dc.typeTexten_US
dc.type.genreJournal Article, Academic Journalen_US
dc.citation.volume119en_US
dc.citation.issue7en_US
dc.citation.spage5638en_US
dc.citation.epage5650en_US
dc.description.statusPublisheden_US
dc.creator.orcid0000-0001-5882-1328en_US

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