HR: 1340h
AN: SM53B-0413 [Abstracts]
TI: Questioning common wisdom on issues of (i) cause of fast magnetic reconnection, (ii) origin and scale
of quadrupole magnetic structure, and (iii) physical reality of Sweet-Parker regime
AU: Briscoe, C
EM: cbriscoe@physics.ucsd.edu
AF: UCSD, 950 Gilman Drive, Dept. of ECE, MC 0407, La Jolla, CA 92093-0407
United States
AU: * karimabadi, h
EM: homa@ece.ucsd.edu
AF: UCSD, 950 Gilman Drive, Dept. of ECE, MC 0407, La Jolla, CA 92093-0407
United States
AU: Krauss-Varban, D
EM: varban@ssl.berkeley.edu
AF: Space Sciences Laboratory, MC 7450
7 Gauss Way
University of California, Berkeley, ca 94720-7450
United States
AU: Huba, J
EM: huba@ppd.nrl.navy.mil
AF: Naval Research Laboratory
Washington, DC 20375-5320, Code 6790, Washington, DC 20375-5320
United States
AU: Daughton, W
EM: william-daughton@uiowa.edu
AF: The University of Iowa
Department of Physics & Astronomy, 06 Van Allen Hall, Iowa City, IA 52242-1479
United States
AU: Omidi, N
EM: omidi@adelphia.net
AF: UCSD, 950 Gilman Drive, Dept. of ECE, MC 0407, La Jolla, CA 92093-0407
United States
AB:
Our recent work brings to question three generally accepted concepts on reconnection: (1) It has been demonstrated that Hall
MHD, hybrid, and full particle simulations yield comparable reconnection rates whereas MHD leads to much smaller rates. The
cause of fast reconnection observed in non-MHD models has been attributed to the dispersive properties of whistler mode. We
show, using Hall-less hybrid simulations, that fast reconnection is achieved due to ion kinetic effects even when whistlers
are non-dispersive. (2) It is well known that Hall currents lead to quadrupole magnetic structure in the reconnection
process and the observations of such structures in spacecraft data is attributed to Hall physics. We show that (i) linear
kinetic theory predicts the presence of the quadrupole structure, (ii) ion kinetics play a significant role in the generation
of the quadrupole structure and the resulting quadrupole structure in a collisionless plasma is always wider than that
predicted by Hall MHD. (c) Resistive MHD studies have predicted conditions for the occurrence of Sweet-Parker and Petschek
regimes. We show that in a kinetic plasma Sweet-Parker is not a stable configuration.
DE: 7835 Magnetic reconnection
DE: 7843 Numerical simulation studies
DE: 2700 MAGNETOSPHERIC PHYSICS
DE: 2724 Magnetopause, cusp, and boundary layers
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting