Evidence of magnetic field switch-off in collisionless magnetic reconnection
2015 (English)In: Astrophysical Journal Letters, ISSN 2041-8205, E-ISSN 2041-8213, Vol. 810, no 2Article in journal (Refereed) Published
The long-term evolution of large domain particle-in-cell simulations of collisionless magnetic reconnection is investigated following observations that show two possible outcomes for collisionless reconnection: toward a Petschek-like configuration or toward multiple X points. In the present simulation, a mixed scenario develops. At earlier time, plasmoids are emitted, disrupting the formation of Petschek-like structures. Later, an almost stationary monster plasmoid forms, preventing the emission of other plasmoids. A situation reminiscent of Petschek’s switch-off then ensues. Switch-off is obtained through a slow shock/rotational discontinuity compound structure. Two external slow shocks (SS) located at the separatrices reduce the in-plane tangential component of the magnetic field, but not to zero. Two transitions reminiscent of rotational discontinuities (RD) in the internal part of the exhaust then perform the final switch-off. Both the SS and the RD are characterized through analysis of their Rankine-Hugoniot jump conditions. A moderate guide field is used to suppress the development of the firehose instability in the exhaust.
Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2015. Vol. 810, no 2
IdentifiersURN: urn:nbn:se:kth:diva-174596DOI: 10.1088/2041-8205/810/2/L19ISI: 000364340000006ScopusID: 2-s2.0-84941031180OAI: oai:DiVA.org:kth-174596DiVA: diva2:877345
FunderEU, FP7, Seventh Framework Programme, 284461
QC 201512072015-12-072015-10-072015-12-07Bibliographically approved