Magnetic reconnection in partially ionized plasmas

• DOI: 10.1063/1.3656960
• Publication Date: 2011-11-09T23:56:30Z
• Authors: Ellen G. Zweibel; Eric Lawrence; Jongsoo Yoo; Hantao Ji; Masaaki Yamada; Leonid M. Malyshkin
• Keywords: Energetic neutral atom; Current sheet; Outflow

We review the theory of magnetic reconnection in weakly ionized gases. The is relevant to interstellar medium, protostellar and protoplanetary disks, outer envelopes cool stars, a new laboratory experiment. In general, partial ionization introduces three effects beyond obvious one: increased resistivity due electron-neutral collisions. First, neutral sheets are steepened by plasma-neutral drift, setting up conditions for reconnection. Second, when ion-neutral friction strong, effective ion mass ρ/ρi, ratio total plasma density. This reduces Alfven speed vA factor ρ/ρi increases skin depth δi ρ/ρi. As result, entrainment neutrals slows MHD but permits onset fast collisionless at larger Lundquist number S, or longer current sheet, than fully case. These effects, taken together, promote fraction order 10% 1%, slowed down much smaller fractions. Finally, can be strong heating mechanism throughout inflow outflow regions. under study Magnetic Reconnection Experiment (MRX).