*Earth Planets Space,* Vol. 53 (No. 6), pp. 463-472, 2001

## The origins of electrical resistivity in magnetic reconnection: Studies by 2D and 3D macro particle simulations

Motohiko Tanaka

Research and Information Center, National Institute for Fusion Science, Toki 509-5292, Japan

(Received May 19, 2000; Revised February 7, 2001; Accepted February 26, 2001)

**Abstract: **
This article argues the roles of electrical resistivity in magnetic reconnection, and also presents recent 3D particle simulations of coalescing magnetized flux bundles. Anomalous resistivity of the lower-hybrid-drift (LHD) instability, and collisionless effects of electron inertia and/or off-diagonal terms of electron pressure tensor are thought to break the frozen-in state that prohibits magnetic reconnection. Studies show that, while well-known stabilization of the LHD instability in high-beta plasma condition makes anomalous resistivity less likely, the electron inertia and/or the off-diagonal electron pressure tensor terms make adequate contributions to break the frozen-in state, depending on strength of the toroidal magnetic field. Large time and space scale particle simulations show that reconnection in magnetized plasmas proceeds by means of electron inertia effect, and that electron acceleration results instead of Joule heating of the MHD picture. Ion inertia contributes positively to reconnection, but ion finite Larmor radius effect does negatively because of charge separation of ions and magnetized electrons. The collisionless processes of the 2D and 3D simulations are similar in essence, and support the mediative role of electron inertia in magnetic reconnection of magnetized plasmas.

Corresponding author E-mail: mtanaka@nifs.ac.jp

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