Investigating high-frequency quasi-periodic oscillations in the 6374 Å red coronal line observed during the total solar eclipse on August 21, 2017

¹ Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China
² Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011, China

Received: 2 December 2023
Accepted: 30 August 2024

Abstract

Context. We present the results of the search for high-frequency quasi-periodic oscillations (HFQPOs) in the 6374-Å red line emission from the solar corona during the 2017 total solar eclipse (TSE).

Aims. The existence of HFQPOs of coronal intensity remains unclear. Motivated by previous observations, this paper focuses on searching for the HFQPOs (> 0.1 Hz) during the 2017 TSE.

Methods. Wavelet analysis tools were used to analyze the radiation intensity oscillations in different height layers, local regions of interest (such as the east coronal loop, west cavity, etc.), and coronal feature points as well as changes in oscillations along coronal feature structures and the kinematic wobble of the coronal magnetic features.

Results. We have observed oscillatory signals at multiple spatial locations, which reveal the existence of quasi-periodic slow magnetoacoustic waves. These signals display periods ranging from approximately 3 to 9 seconds, with a notable focus on periods around 4 seconds.

Conclusions. High-frequency quasi-periodic slow magnetoacoustic oscillations (with periods less than 9.63 seconds) have been identified in the inner corona (at heights less than 1.4 R_⊙) in the 6374 Å red coronal line radiation.