P. H. Diamond2),
C. J. McDevitt2),
(TH/P2-19) Interaction of Drift-Tearing (Mesoscopic) Modes with Coherent and Turbulent Microscopic Structures
1) MIT, Cambridge, United States of America
2) UCSD, San Diego, United States of America
Abstract. The excitation and evolution of the mesoscopic modes involving magnetic reconnection remains a challenging theoretical issue as experiments on high temperature plasmas provide evidence for their presence while the original and well established theories indicate that they should be hampered by the effect of electron Landau damping or longitudinal electron thermal conductivity. Considering the interaction of these modes with a relevant kind of background micro-structure (coherent or turbulent) then becomes a necessary development of the theory. Within this general framework, electromagnetic electron temperature gradient driven modes that produce localized magnetic reconnection at the scale of the collisionless electron inertial skin depth are considered the most appropriate source of relevant microstructures and are shown to sustain a significant electron temperature variation along the field lines defeating the effect of the longitudinal thermal conductivity. As an alternative and as a minimally working self-consistent model, we analyze the coupling between a tearing mode and electrostatic drift wave turbulence. In this case the principal effect of the drift waves is to pump the tearing mode via negative viscosity, consistent with the classical notion of the inverse cascade in quasi-2D turbulence.
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