Dear user, changes will soon be made to Orfeo. We will undertake the migration to a new version, another environment (and therefore a new URL: https://orfeo.belnet.be/) and another provider. Belnet will take over the management of Orfeo in the future. For you, this means that no changes, modifications or uploads can be made to the database Orfeo from the 1st of December 2021 to the 10th of December 2021. The database remains available for consultation. From the 10th of December 2021 onwards, you can reach Orfeo via the new url https://orfeo.belenet.be/. Our apologies for the inconvenience.

Show simple item record

dc.contributor.authorPierrard, V.
dc.contributor.authorRipoll, J.-F.
dc.contributor.authorCunningham, G.
dc.contributor.authorBotek, E.
dc.contributor.authorSantolik, O.
dc.contributor.authorThaller, S.
dc.contributor.authorKurth, W.S.
dc.contributor.authorCosmides, M.
dc.contributor.editor
dc.date2021
dc.date.accessioned2021-08-02T15:12:59Z
dc.date.available2021-08-02T15:12:59Z
dc.identifier.urihttps://orfeo.kbr.be/handle/internal/7942
dc.descriptionWe compare ESA PROBA-V observations of electron flux at LEO with those from the NASA Van Allen Probes mostly at MEO for October 2013. Dropouts are visible at all energy during four storms from both satellites. Equatorially trapped electron fluxes are higher than at LEO by 102 (<1 MeV) to 105 (>2.5 MeV). We observe a quite isotropic structure of the outer belt during quiet times, contrary to the inner belt, and pitch angle dependence of high energy injection. We find a very good overlap of the outer belt at MEO and LEO at ∼0.5 MeV. We use test-particle simulations of the energetic electrons trapped in the terrestrial magnetic field to study the outer radiation belt electron flux changes during geomagnetic storms. We show that the Dst (Disturbance storm time) effect during the main phase of a geomagnetic storm results in a betatron mechanism causing outward radial drift and a deceleration of the electrons. This outward drift motion is energy independent, pitch angle-dependent, and represents a significant distance (∼1 L-shell at L = 5 for moderate storms). At fixed L-shell, this causes a decay of the LEO precipitating flux (adiabatic outward motion), followed by a return to the normal state (adiabatic inward motion) during main and recovery phases. Dst effect, associated with magnetopause shadowing and radial diffusion can explain the main characteristics of outer radiation belt electron dropouts in October 2013. We also use Fokker-Planck simulations with event-driven diffusion coefficients at high temporal resolution, to distinguish instantaneous loss from the gradual scattering that depopulates the slot region and the outer belt after storms. Simulations reproduce the slot formation and the gradual loss in the outer belt. The typical energy dependence of these losses leads to the absence of scattering for relativistic and ultra-relativistic electrons in the outer belt, oppositely to dropouts.
dc.languageeng
dc.titleObservations and simulations of dropout events and flux decays in October 2013: Comparing MEO equatorial with LEO polar orbit
dc.typeArticle
dc.subject.frascatiPhysical sciences
dc.audienceScientific
dc.subject.freeenergetic particles
dc.subject.freegeomagnetic storms
dc.subject.freeradiation belts
dc.subject.freerelativistic electrons
dc.source.titleJournal of Geophysical Research: Space Physics
dc.source.volume126
dc.source.issue6
dc.source.pagee2020JA028850
Orfeo.peerreviewedYes
dc.identifier.doi10.1029/2020JA028850


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record