SoCal Plasma Zoom Seminar: New Insights into Plasma Turbulence

The current understanding of plasma turbulence in the MHD regime suggests that turbulent eddies become progressively more elongated structures in the plane perpendicular to the local mean magnetic field. Using recent results from reconnection theory, we argue that such eddies must inevitably fall prey to the tearing instability.  As a result, there is a transition, in the inertial range, to a tearing (reconnection)-mediated turbulent cascade, where the spectral scaling k^{-11/5} is predicted.These results can be extended to collisionless plasmas; in the different regimes of interest that have been explored, the magnetic energy spectral scaling is invariably found to be in the range k^{-8/3} to k^{-3}, consistent with many observations.