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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