Drift waves in the corona: heating and acceleration of ions at frequencies far below the gyro frequency

TL;DR

This paper investigates how drift wave instabilities in the solar corona can lead to rapid particle heating and acceleration, highlighting the importance of stochastic heating mechanisms previously overlooked in coronal heating models.

Contribution

It demonstrates that inhomogeneous coronal plasma supports fast-growing drift waves capable of causing significant stochastic heating, a process not previously considered in coronal heating studies.

Findings

Drift waves grow rapidly with rates comparable to plasma frequency.

Stochastic heating can exceed the energy requirements for coronal heating.

Particle dynamics analysis reveals a higher threshold for heating than fluid analysis.

Abstract

In the solar corona, several mechanisms of the drift wave instability can make the mode growing up to amplitudes at which particle acceleration and stochastic heating by the drift wave take place. The stochastic heating, well known from laboratory plasma physics where it has been confirmed in numerous experiments, has been completely ignored in past studies of coronal heating. However, in the present study and in our very recent works it has been shown that the inhomogeneous coronal plasma is, in fact, a perfect environment for fast growing drift waves. As a matter of fact, the large growth rates are typically of the same order as the plasma frequency. The consequent heating rates may exceed the required values for a sustained coronal heating by several orders of magnitude. Some aspects of these phenomena are investigated here. In particular the analysis of the particle dynamics within the growing wave is compared with the corresponding fluid analysis. While both of them predict the stochastic heating, the threshold for the heating obtained from the single particle analysis is higher. The explanation for this effect is given.