Electron magnetohydrodynamic simulations of magnetic island coalescence

Citation
Jc. Dorelli et J. Birn, Electron magnetohydrodynamic simulations of magnetic island coalescence, PHYS PLASMA, 8(9), 2001, pp. 4010-4019
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
PHYSICS OF PLASMAS
ISSN journal
1070-664X → ACNP
Volume
8
Issue
9
Year of publication
2001
Pages
4010 - 4019
Database
ISI
SICI code
1070-664X(200109)8:9<4010:EMSOMI>2.0.ZU;2-0
Abstract
The role of electrons in driving magnetic island coalescence in the electro n magnetohydrodynamic limit is investigated. In particular, the dependence of the coalescence time t(c)((f)) (defined as the time required for a fixed fraction f of the initial island magnetic flux to reconnect) on the resist ivity eta for constant Lundquist number S-lambda (defined in terms of the i sland wavelength lambda) is studied. Two distinct island coalescence regime s are observed: (1) a "resistive diffusion regime" where t(c)((f)) proporti onal to t(w)/eta (t(w) equivalent to (lambda (2)/Omega (ci)d(i)(2)), where Omega (ci) is the ion cyclotron frequency, and d(i) is the ion inertial len gth), and (2) an "electron driven regime" where t(c)((f)) proportional to t (w). Defining the "ion Lundquist number," S-i equivalent to S(lambda)d(i)/l ambda, the resistive diffusion regime is observed when S-i less than or sim ilar to 50, while the electron driven regime is observed when S-i greater t han or similar to 50. In the electron driven regime, the coalescence time i s insensitive to S-i over the range 50 less than or similar to S-i less tha n or similar to 250. (C) 2001 American Institute of Physics.