# Oscillations Accompanying a He I 10830 {\AA} Negative Flare in a Solar Facula II. Response of the Transition Region and Corona

## TL;DR

This study investigates how flare-induced oscillations propagate through the solar atmosphere, revealing delays and wave types in transition region and coronal layers using multi-instrument observations.

## Contribution

It provides new insights into the propagation of flare-triggered oscillations from the corona to the chromosphere and transition region, identifying slow magnetoacoustic waves and their timing.

## Key findings

- 2-minute oscillations appeared first in RHESSI data and later in SDO and chromospheric lines.
- Delay of 7 minutes between coronal and chromospheric signals indicates wave propagation from corona to chromosphere.
- Observed slow magnetoacoustic waves in different atmospheric layers.

## Abstract

We studied oscillations related to flare SOL2012-09-21T02:19 in the transition region and chromosphere based on Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Solar Dynamics Observatory (SDO) data, as well as data from a ground-based observatory. We found that 2-minute oscillations triggered by the flare first appeared in the RHESSI channels then subsequently showed up in the SDO 171 {\AA} and 304 {\AA} channels and after that in the chromospheric He I 10830 {\AA} line. The delay of the chromospheric signal compared to the RHESSI signal is 7 minutes, which indicates that the wave perturbation propagated from the corona to the chromosphere. We used the sharp increase in 3- and 5-minute oscillations during the flare in the lower atmosphere to trace the propagation of the oscillation trains to the transition region and corona. The results show that the 171 {\AA} channel signals lagged behind the photospheric and chromospheric signals by 200 s on average. We suggest that we observed slow magnetoacoustic waves both in the case of 2-minute oscillations propagating downwards from the corona and in the case of 3- and 5-minute oscillations leaking to the corona from beneath.