Collisionless Magnetic Reconnection: The Origin of
Electrical Resistivity or Something Else ?
(continued)



What happens at the X-point ?

The plasma current that is induced at the X-point by Faraday's law as reconnection proceeds is carried out with moving electrons. Here, we have to recall that electrical resistivity was brought into the MHD theory to dissipate the X-point current which blocks magnetic reconnection by its repulsive forces against a newly incoming plasma into that region. Hence, no necessity of such an artificial term if other mechanism of reducing the X-point current exists, and it really does, as it was shown by my macro-particle simulations.

History Repeats Itself ?
For the sake of impartiality, we refer to a pre-existing theory by Dr.Speicer. In late 1960s he thought of electrons as the agent to carry out the X-point current, which was termed electron inertia resistivity. However, his theory relied on several assumptions, and because of criticism by H.Alfven and uprising popularity of anomalous resistivity - direct conversion of magnetic fusion theory, Speicer's theory was forgotten.

Many researchers studied plasma instabilities and anomalous resistivity in 1970s. Ironically, I was engaging in the study of the LHD (lower-hybrid drift) instability as a possible origin of dissipation in my PhD thesis work. Ten years later, I came back to the subject, and proved the origin of the dissipation for magnetic reconnection using my macro-particle simulation code.


References:
First proof of collisionless magnetic reconnection
Phys.Plasmas 2, 2920 (1995).

Roles of protons and electrons in magnetic reconnection
Phys.Plasmas, 3, 4010 (1996).


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