Modelling of transverse oscillations driven by p-modes in short coronal loops

TL;DR

This paper models decayless transverse oscillations in short coronal loops driven by p-modes, explaining observed period differences and suggesting p-modes as a potential energy source for coronal heating.

Contribution

It demonstrates through MHD simulations that p-modes can excite both short-period and 5-minute oscillations in coronal loops, advancing understanding of their origin.

Findings

Both oscillation types can be excited by p-modes in a single loop.

The 5-minute oscillation is directly driven by footpoint p-modes.

Shorter periods are identified as kink eigenmodes of different harmonics.

Abstract

Recent observations have revealed two types of decayless transverse oscillations in short coronalloops: one with short periods scaling with loop lengths, and the other with longer periods that exhibit a peak at around 5 min in the period distribution. To understand such a difference in period, we work in the framework of ideal MHD and model a short coronal loop embedded in an atmosphere with density stratification from the chromosphere to the corona. An inclined p-mode-like driver with a period of 5 min is launched at one loop footpoint. It is discovered that two types of decayless transverse oscillations can be excited in the loop. We interpret the 5 min periodicity as being directly driven by the footpoint driver, while the others, with periods of several tens of seconds, are regarded as kink eigenmodes of different harmonics. Therefore, our simulation shows that both types of decayless oscillations found in observations can be excited by p-modes in one short coronal loop. This study extends our understanding of ubiquitous decayless transverse oscillations in the corona. Furthermore, it suggests that p-modes could be an important energy source for coronal heating by driving decayless transverse oscillations.