Speaker: Alfred Mallet
Affiliation: Space Sciences Laboratory, UC Berkeley

Abstract:
Parker Solar Probe is revolutionising our understanding of turbulence in the solar wind and corona. The “standard model” of anisotropic, low-frequency Alfvénic turbulence predicts little ion heating, because the magnetic moment is conserved to all orders in the low-frequency expansion. This is in stark contrast to the observed dominance of perpendicular ion heating in the corona and low-beta solar wind.
In this talk, I present a new theoretical picture of perpendicular ion heating that unifies previous models of stochastic heating, cyclotron heating, and heating in guide-field reconnection. An important advantage of this new model is that it is easy to apply to intermittent turbulence. I demonstrate that accounting for rare, large-amplitude coherent fluctuations, naturally produced by the turbulent dynamics, can dramatically enhance the predicted efficiency of ion heating, resolving the previous discrepancies between theory and space measurements. This suggests that intermittency is not just a statistical curiosity, but a necessary component of any theory purporting to describe heating in plasma turbulence.

Zoom/Meeting Link: https://ucla.zoom.us/j/97828298609?pwd=kbJEOQ2YHlxZifxQW1uT7SQkiBmchT.1

Submitted by: Omar Abuassaf (oabuassaf@epss.ucla.edu)