Interplay between intermittency and dissipation in collisionless plasma turbulence

TL;DR

This paper investigates how intermittency influences two damping mechanisms in collisionless plasma turbulence, revealing that stochastic heating is enhanced by intermittency and affects turbulence statistics near the ion gyroscale.

Contribution

It provides a detailed analysis of the interplay between intermittency and damping mechanisms, highlighting the differential impact on stochastic heating and Landau damping.

Findings

Linear Landau damping efficiency remains unaffected by intermittency.

Stochastic heating becomes more effective in intermittent turbulence.

Stochastic heating causes a decrease in kurtosis near the ion gyroscale.

Abstract

We study the damping of collisionless Alfv\'enic turbulence by two mechanisms: stochastic heating (whose efficiency depends on the local turbulence amplitude $\delta z_\lambda$) and linear Landau damping (whose efficiency is independent of $\delta z_\lambda$), describing in detail how they affect and are affected by intermittency. The overall efficiency of linear Landau damping is not affected by intermittency in critically balanced turbulence, while stochastic heating is much more efficient in the presence of intermittent turbulence. Moreover, stochastic heating leads to a drop in the scale-dependent kurtosis over a narrow range of scales around the ion gyroscale.