Origin of resistivity in reconnection

• Published in: Earth, planets, and space Vol. 53; no. 6; pp. 453 - 462
• Main Author: TREUMANN, Rudolf A
• Format: Journal Article
• Language: English
• Published: Tokyo Terra 01.01.2001; Springer Nature B.V
• Subjects: Astronomy; Current sheets; Diamagnetism; Earth, ocean, space; Electrical resistivity; Exact sciences and technology; Fundamental aspects of astrophysics; Fundamental astronomy and astrophysics. Instrumentation, techniques, and astronomical observations; Magnetic fields; Magnetohydrodynamics and plasmas; Space plasmas; Spacecraft; Magnetic reconnection; Ohm law; Ion acoustic waves; Anomalous resistivity; Current layers; Drift waves; Collisionless plasma; Buneman instability; Models; Magnetic fields; Diffusivity; Electrostatic turbulence
• ISSN: 1343-8832; 1880-5981; 1880-5981
• DOI: 10.1186/BF03353256

Resistivity is believed to play an important role in reconnection leading to the distinction between resistive and collisionless reconnection. The former is treated in the Sweet-Parker model of long current sheets, and the Petschek model of a small resistive region. Both models in spite of their different dynamics attribute to the violation of the frozen-in condition in their diffusion regions due to the action of resistivity. In collisionless reconnection there is little consensus about the processes breaking the frozen-in condition. The question is whether anomalous processes generate sufficient resistivity or whether other processes free the particles from slavery by the magnetic field. In the present paper we review processes that may cause anomalous resistivity in collisionless current sheets. Our general conclusion is that in space plasma boundaries accessible to in situ spacecraft, wave levels have always been found to be high enough to explain the existence of large enough local diffusivity for igniting local reconnection. However, other processes might take place as well. Non-resistive reconnection can be caused by inertia or diamagnetism.