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Titolo:
Alfvenic collisionless magnetic reconnection and the Hall term
Autore:
Shay, MA; Drake, JF; Rogers, BN; Denton, RE;
Indirizzi:
Dartmouth Coll, Dept Phys & Astron, Hanover, NH 03755 USA Dartmouth Coll Hanover NH USA 03755 Phys & Astron, Hanover, NH 03755 USA Univ Maryland, Inst Plasma Res, College Pk, MD 20742 USA Univ Maryland College Pk MD USA 20742 lasma Res, College Pk, MD 20742 USA
Titolo Testata:
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
fascicolo: A3, volume: 106, anno: 2001,
pagine: 3759 - 3772
SICI:
0148-0227(20010301)106:A3<3759:ACMRAT>2.0.ZU;2-P
Fonte:
ISI
Lingua:
ENG
Soggetto:
CURRENT SHEETS; MAGNETOTAIL RECONNECTION; ELECTRON DISSIPATION; X-LINE; INSTABILITY; PLASMAS; MAGNETOPAUSE; SIMULATION; FIELDS; REGION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
32
Recensione:
Indirizzi per estratti:
Indirizzo: Shay, MA Dartmouth Coll, Dept Phys & Astron, Hanover, NH 03755 USA Dartmouth Coll Hanover NH USA 03755 stron, Hanover, NH 03755 USA
Citazione:
M.A. Shay et al., "Alfvenic collisionless magnetic reconnection and the Hall term", J GEO R-S P, 106(A3), 2001, pp. 3759-3772

Abstract

The Geospace Environment Modeling (GEM) Challenge Harris current sheet problem is simulated in 2 1/2 dimensions using full particle, hybrid, and HallMHD simulations. The same gross reconnection rater is found in all of the simulations independent of the type of code used, as long as the Hall term is included. In addition, the reconnection rate is independent of the mechanism which breaks the frozen-in flux condition, whether it is electron inertia or grid scale diffusion. The insensitivity to the mechanism which breaks the frozen-in condition is a consequence of whistler waves, which controlthe plasma dynamics at the small scales where the ions become unmagnetized. The dispersive character of whistlers, in which the phase velocity increases with decreasing scale size, allows the flux of electrons flowing away from the dissipation region to remain finite even as the strength of the dissipation approaches zero. As a consequence, the throttling of the reconnection process as a result of the small scale size of the dissipation region, which occurs in the magnetohydrodynamic model, no longer takes place. The important consequence is that the minimum physical model necessary to produce physically correct reconnection rates is a Hall MHD description which includes the Hall term in Ohm's law. A density depletion layer, which lies just downstream from the magnetic separatrix, is identified and linked to the strong in-plane Hall currents which characterize kinetic models of magneticreconnection.

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Documento generato il 04/04/20 alle ore 15:26:32