Quasi-periodic pulsations(QPPs)are very common oscillation features during solar flares,which have been observed in almost the entire wavelengths.However,the flare-related QPPs with double periods in the Lyα emission...Quasi-periodic pulsations(QPPs)are very common oscillation features during solar flares,which have been observed in almost the entire wavelengths.However,the flare-related QPPs with double periods in the Lyα emission,particularly within a period ratio of about 2,were rarely detected.In this paper,we report the QPPs with double periods in the full-disk Lyαemission during the impulsive phase of four solar flares,i.e.,SOL2016-Feb-12,SOL2014-Oct-24,SOL2014-Jun-10,and SOL2012-Nov-21.The fulldisk Lyαfluxes were recorded by the extreme-ultraviolet sensor on board the Geostationary Operational Environmental Satellite.Then,the quasi-periods are estimated by the Markov chain Monte Carlo(MCMC)sampling techniques.Finally,the double periods of around 3 and 1.5 min are detected in Lyαemissions,and their period ratio is roughly equal to 2.The 3-min QPP could also be detected in the local light curves measured by the Atmospheric Imaging Assembly at wavelengths of 304 and 1600A.Our observations suggest that the double periodic QPPs could be regarded as the fundamental and harmonic modes of acoustic waves,which should be helpful to understand magnetohydrodynamic waves in the solar chromosphere.However,we cannot rule out that the double periods are each caused by a different generation mechanism.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11973092,12073081,11873095,11790302 and11729301)the Strategic Pioneer Program on Space Science of Chinese Academy of Sciences(Grant Nos.XDA15052200 and XDA15320301)+1 种基金the CAS Key Laboratory of Solar Activity(Grant No.KLSA202003)The Laboratory No.2010DP173032。
文摘Quasi-periodic pulsations(QPPs)are very common oscillation features during solar flares,which have been observed in almost the entire wavelengths.However,the flare-related QPPs with double periods in the Lyα emission,particularly within a period ratio of about 2,were rarely detected.In this paper,we report the QPPs with double periods in the full-disk Lyαemission during the impulsive phase of four solar flares,i.e.,SOL2016-Feb-12,SOL2014-Oct-24,SOL2014-Jun-10,and SOL2012-Nov-21.The fulldisk Lyαfluxes were recorded by the extreme-ultraviolet sensor on board the Geostationary Operational Environmental Satellite.Then,the quasi-periods are estimated by the Markov chain Monte Carlo(MCMC)sampling techniques.Finally,the double periods of around 3 and 1.5 min are detected in Lyαemissions,and their period ratio is roughly equal to 2.The 3-min QPP could also be detected in the local light curves measured by the Atmospheric Imaging Assembly at wavelengths of 304 and 1600A.Our observations suggest that the double periodic QPPs could be regarded as the fundamental and harmonic modes of acoustic waves,which should be helpful to understand magnetohydrodynamic waves in the solar chromosphere.However,we cannot rule out that the double periods are each caused by a different generation mechanism.
