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Titolo:
Geospace Environmental Modeling (GEM) Magnetic Reconnection Challenge
Autore:
Birn, J; Drake, JF; Shay, MA; Rogers, BN; Denton, RE; Hesse, M; Kuznetsova, M; Ma, ZW; Bhattacharjee, A; Otto, A; Pritchett, PL;
Indirizzi:
Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA Univ Calif Los Alamos Natl Lab Los Alamos NM USA 87545 amos, NM 87545 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 NASA, Goddard Space Flight Ctr, Electrodynam Branch, Greenbelt, MD 20771 USA NASA Greenbelt MD USA 20771 Electrodynam Branch, Greenbelt, MD 20771 USA Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA Univ Iowa Iowa City IA USA 52242 t Phys & Astron, Iowa City, IA 52242 USA Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA Univ Alaska Fairbanks AK USA 99775 Inst Geophys, Fairbanks, AK 99775 USA Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA UnivCalif Los Angeles Los Angeles CA USA 90095 Los Angeles, CA 90095 USA
Titolo Testata:
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
fascicolo: A3, volume: 106, anno: 2001,
pagine: 3715 - 3719
SICI:
0148-0227(20010301)106:A3<3715:GEM(MR>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
X-LINE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
16
Recensione:
Indirizzi per estratti:
Indirizzo: Birn, J Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USAUniv Calif Los Alamos Natl Lab POB 1663 Los Alamos NM USA 87545 SA
Citazione:
J. Birn et al., "Geospace Environmental Modeling (GEM) Magnetic Reconnection Challenge", J GEO R-S P, 106(A3), 2001, pp. 3715-3719

Abstract

The Geospace Environmental Modeling (GEM) Reconnection Challenge project is presented and the important results, which are presented in a series of companion papers, are summarized. Magnetic reconnection is studied in a simple Harris sheet configuration with a specified set of initial conditions, including a finite amplitude, magnetic island perturbation to trigger the dynamics. The evolution of the system is explored with a broad variety of codes, ranging from fully electromagnetic particle in cell (PIC) codes to conventional resistive magnetohydrodynamic (MHD) codes, and the results are compared. The goal is to identify the essential physics which is required to model collisionless magnetic reconnection. All models that include the Hall effect in the generalized Ohm's law produce essentially indistinguishable rates of reconnection, corresponding to nearly Alfvenic inflow velocities. Thus the rate of reconnection is insensitive to the specific mechanism whichbreaks the frozen-in condition, whether resistivity, electron inertia, or electron thermal motion. The reconnection rate in the conventional resistive MHD model, in contrast, is dramatically smaller unless a large localized or current dependent resistivity is used. The Hall term brings the dynamicsof whistler waves into the system. The quadratic dispersion property of whistlers (higher phase speed at smaller spatial scales) is the key to understanding these results. The implications of these results fbr trying to model the global dynamics of the magnetosphere are discussed.

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Documento generato il 09/04/20 alle ore 07:37:11