Very Long-period Pulsations before the Onset of Solar Flares

Abstract

Solar flares are the most powerful explosions occurring in the solar system, which may lead to disastrous space weather events and impact various aspects of our Earth. So far, it is still a big challenge in modern astrophysics to understand the origin of solar flares and predict their onset. Based on the analysis of soft X-ray emission observed by the Geostationary Operational Environmental Satellite (GOES), this work reported a new discovery of very long-periodic pulsations occurred in the preflare phase before the onset of solar flares (preflare-VLPs). These pulsations are typically with period of 8 - 30 min and last for about 1 - 2 hours. They are possibly generated from LRC oscillations of plasma loops where electric current dominates the physical process during magnetic energy accumulation in the source region. The preflare-VLP provides an essential information for understanding the triggering mechanism and origin of solar flares, and may help us to response to solar explosions and the corresponding disastrous space weather events as a convenient precursory indicator.

9 pages, 3 figures, 1 table, accepted by ApJ

References in corpus (5)

• Toward Reliable Benchmarking of Solar Flare Forecasting Methods
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Cited by in corpus (16)

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• Detections of Multi-Periodic Oscillations during a Circular Ribbon Flare
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• Very long-periodic pulsations detected simultaneously in a white-light flare and sunspot penumbra
• Multi-instrument Comparative Study of Temperature, Number Density, and Emission Measure during the Precursor Phase of a Solar Flare
• The early evolution of solar flaring plasma loops
• Detecting fast-variation pulsations in solar hard X-ray and radio emissions
• Investigating Pre-flare Signatures in Spectroscopic Observations of an X9-class Solar Flare
• Power-law Indices of EUV Intensity Power Spectrum in Flaring Coronal Active Regions