Frequency Distribution of Acoustic Oscillation in the Solar Atmosphere During Flare Event

Abstract

Abstract We present a study of multi-wavelength observations, of a C 2.3 solar flare in Active Region NOAA 12353, observed on 2015 May 23, which reveal new properties of acoustic waves in the flaring region. The space-, and ground-based data measured by the HELioseismological Large Regions Interferometric Device, operating at the Vacuum Tower Telescope, the Atmospheric Imaging Assembly (AIA), and Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory, were used in this paper. First, using power spectra of solar oscillations, we identified the dominant frequencies and their location at seven different atmospheric levels before and after the flare event. Second, based on AIA observations taken in six Extreme Ultraviolet filters, we derived Differential Emission Measure (DEM) profiles and DEM maps of the flare. Finally, we confirm the sigma shape of the magnetic field in the active area, directly related to the flare. Our results are as follows: the high-frequency waves (ν > 5 mHz) in the photosphere, in both cases, before and after the flare, are generated at the footpoints of the chromospheric loop, while in the chromosphere (Hα line), before the event the power enhancement exhibits the maximum of flare emission, and after the eruption the enhancement by all frequencies is observed only in the post-flare loop area. Moreover, the power of oscillation in the pores surrounding the area before the flare has a random character, while after the flare oscillation power is concentrated in the pore, and weakened outside of. We conclude that accurate detection of high-frequency acoustic waves in active regions can lead to faster and easier prediction of high-energy events.