Thumbnail
Access Restriction
Open

Author Khabarova, Olga V. ♦ Zank, Gary P.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ ACCELERATION ♦ ELECTRONS ♦ HELIOSPHERE ♦ KEV RANGE ♦ MAGNETIC FIELDS ♦ MAGNETIC ISLANDS ♦ MAGNETIC RECONNECTION ♦ MEV RANGE 01-10 ♦ PROTONS ♦ SOLAR PARTICLES ♦ SOLAR WIND ♦ SUN ♦ TAIL IONS ♦ TRANSPORT THEORY ♦ TRAPPING ♦ TURBULENCE
Abstract We provide evidence for particle acceleration up to ∼5 MeV at reconnecting current sheets in the solar wind based on both case studies and a statistical analysis of the energetic ion and electron flux data from the five Advanced Composition Explorer Electron, Proton, and Alpha Monitor (EPAM) detectors. The case study of a typical reconnection exhaust event reveals (i) a small-scale peak of the energetic ion flux observed in the vicinity of the reconnection exhaust and (ii) a long-timescale atypical energetic particle event (AEPE) encompassing the reconnection exhaust. AEPEs associated with reconnecting strong current sheets last for many hours, even days, as confirmed by statistical studies. The case study shows that time-intensity profiles of the ion flux may vary significantly from one EPAM detector to another partially because of the local topology of magnetic fields, but mainly because of the impact of upstream magnetospheric events; therefore, the occurrence of particle acceleration can be hidden. The finding of significant particle energization within a time interval of ±30 hr around reconnection exhausts is supported by a superposed epoch analysis of 126 reconnection exhaust events. We suggest that energetic particles initially accelerated via prolonged magnetic reconnection are trapped and reaccelerated in small- or medium-scale magnetic islands surrounding the reconnecting current sheet, as predicted by the transport theory of Zank et al. Other mechanisms of initial particle acceleration can contribute also.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2017-07-01
Publisher Place United States
Journal Astrophysical Journal
Volume Number 843
Issue Number 1


Open content in new tab

   Open content in new tab