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Old 13th February 2009, 11:49 PM   #1221
Tim Thompson
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Lightbulb Comments on magnetic Reconnection

Originally Posted by Michael Mozina View Post
Magnetic lines lack physical substance, .... and they are physically *incapable* of "reconnecting". Did any of you folks take a class in basic electronics? .... You clearly don't know much about electrical engineering or you would never claim you can get energy from "magnetic reconnection".
Representative comments; clearly Mr. Mozina, and others no doubt, reject the concept of "magnetic reconnection" altogether. This is an uncomfortable position to take, since "magnetic reconnection" is directly observed in controlled laboratory plasma physics experiments (i.e., Lawrence & Gekelman, 2008; Cheng, et al., 2008; Yamada, et al., 2007; Yamada, Ren & Ji, 2007; Yamada, et al., 2006; Sarff, et al., 2005 & etc.; Yamada, 1999 reviews the previous 20 years of laboratory plasma studies of magnetic reconnection).

The argument that magnetic field lines are without physical substance, and therefore cannot reconnect, is purely a semantic argument with no basis in physics. The lines represent the topology of the magnetic field, and the change in the topology of the magnetic field is the physical manifestation of magnetic reconnection. The phenomenological consequence is a transfer of energy from the magnetic field (which loses internal energy) to the plasma (which gains kinetic energy). As noted in the papers cited above, the observations of laboratory plasma are consistent with the predictions based on magnetic reconnection theory. Furthermore, we know that double layers are not involved, because the topology of the field is observable before, during and after reconnection, so double layers would be obviously visible. Furthermore, the result of a collapsing double layer is observationally distinguishable from that of reconnection. The observations in fact are consistent with the latter, and inconsistent with the former.

Magnetic reconnection is a phenomenon verified by controlled laboratory plasma physics experiments. See, for instance, the Magnetic Reconnection Experiment (MRX) at the Princeton University Plasma Physics Laboratory. MRX has been measuring magnetic reconnection in laboratory plasma since 1995, but there are experimental observations of reconnection that predate that.

One must also observe that the theory of magnetic reconnection is well developed, and is commonly described in plasma physics text books (i.e., Magnetic Reconnection: MHD Theory and Applications, Priest & Forbes, Cambridge University Press, 2000, concentrates in detail on magnetic reconnection; other books typically include chapters on magnetic reconnection, i.e., Fundamentals of Plasma Physics, Paul M. Bellan, Cambridge University Press, 2006 (Bellan heads the Bellan Plasma Group at Caltech, which does an outstanding job of simulating solar prominences in in the laboratory); Plasma Physics for Astrophysics, Russell M. Kulsrud, Princeton University Press, 2005; The Physics of Plasmas, Boyd & Sanderson, Cambridge University Press, 2003; Nonlinear Magnetohydrodynamics, Dieter Biskamp, Cambridge Monographs on Plasma Physics, 1993).

Magnetic reconnection, as a physical phenomenon, regardless of the argument over words, is an integral & fundamental aspect of plasma physics. Denying the validity of magnetic reconnection is quite the same as simply denying the validity of laboratory plasma physics altogether.
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