Quasi-periodic Pulsation Detected in Lyα Emission During Solar Flares
Abstract
We investigated the quasi-periodic pulsation (QPP) in Lyα, X-ray, and extreme-ultraviolet (EUV) emissions during two solar flares, I.e., an X-class (SOL2012-01-27T) and a C-class (SOL2016-02-08T). The full-disk Lyα and X-ray flux during these solar flares were recorded by the EUV Sensor and X-Ray Sensor on board the Geostationary Operational Environmental Satellite. The flare regions were located from the EUV images measured by the Atmospheric Imaging Assembly. The QPP could be identified as a series of regular and periodic peaks in the light curves, and its quasi-periodicity was determined from the global wavelet and Fourier power spectra. A quasi-periodicity at about 3 minutes is detected during the impulsive phase of the X-class flare, which could be explained as the acoustic wave in the chromosphere. Interestingly, a quasi-periodicity at roughly 1 minute is discovered during the entire evolutionary phases of solar flares, including the precursor, impulsive, and gradual phases. This is the first report of 1 minute QPP in the Lyα emission during solar flares, in particular during the flare precursor. It may be interpreted as a self-oscillatory regime of the magnetic reconnection, such as magnetic dripping.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2020
- DOI:
- 10.3847/1538-4357/ab7cd1
- arXiv:
- arXiv:2003.01877
- Bibcode:
- 2020ApJ...893....7L
- Keywords:
-
- Solar flares;
- Solar oscillations;
- Solar chromosphere;
- Solar ultraviolet emission;
- Solar x-ray emission;
- 1496;
- 1515;
- 1479;
- 1533;
- 1536;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 21 pages, 7 figures, accepted for publication in The Astrophysical Journal