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Variation in the Flaring Potential of Different sunspot Groups During Different Phases of Solar Cycles 23 and 24

Research in Astronomy and Astrophysics 2024年第2期24卷 144-153页

作者： Abha Singh Anurag Chaudhari Gyaneshwar Sharma A.K.Singh Department of Physics T.D.P.G.College Jaunpur-222002India Department of Physics Banaras Hindu UniversityVaranasi-221005India

In this present study,we have analyzed different types of X-ray solar flares(C,M,and X classes)coming out from different classes of sunspot groups(SSGs).The data which we have taken under this study cover the duration of 24 yr from 1996 to 2019.During this,we observed a total of 15015 flares(8417 in SC-23 and 6598 in SC-24)emitted from a total of 33780 active regions(21746 in SC-23 and 12034 in SC-24)with sunspot only.We defined the flaring potential or flare-production potential as the ratio of the total number of flares produced from a particular type of SSG to the total number of the same-class SSGs observed on the solar surface.Here we studied yearly changes in the flaring potential of different McIntosh class groups of sunspots in different phases of SC-23 and 24.In addition,we investigated yearly variations in the potential of producing flares by different SSGs(A,B,C,D,E,F,and H)during different phases(ascending,maximum,descending,and minimum)of SC-23 and 24.These are our findings:(1)D,E,and F SSGs have the potential of producing flares≥8 times greater than A,B,C and H SSGs;(2)The larger and more complex D,E,and F SSGs produced nearly 80%of flares in SC-23 and 24;(3)The A,B,C and H SSGs,which are smaller and simpler,produced only 20%of flares in SC-23 and 24;(4)The biggest and most complex SSGs of F-class have flaring potential 1.996 and 3.443 per SSG in SC-23 and 24,respectively.(5)The potential for producing flares in each SSG is higher in SC-24 than in SC-23,although SC-24 is a weaker cycle than SC-23.(6)The alterations in the number of flares(C+M+X)show different time profiles than the alterations in sunspot numbers during SC-23 and 24,with several peaks.(7)The SSGs of C,D,E,and H-class have the highest flaring potential in the descending phase of both SC-23 and 24.(8)F-class SSGs have the highest flaring potential in the descending phase of SC-23 but also in the maximum phase of SC-24.

关键词： (sun:)sunspots-sun flares-sun activity-sun magnetic fields-sun filaments-prominences

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Analysis of Ground Level Enhancement Events of 1989 September 29;2001April 15 and 2005 January 20

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Research in Astronomy and Astrophysics 2022年第10期22卷 86-102页

作者： R.E.Ugwoke A.A.Ubachukwu J.O.Urama O.Okike J.A.Alhassan A.E.Chukwude Department of Physics Federal University of Technology OwerriImo state Nigeria Department of Physics and Astronomy University of NigeriaNsukkaNigeria Department of Industrial Physics Ebonyi State UniversityAbakalikiNigeria

We present the results of analyses of the ground level enhancements(GLEs)of cosmic ray(CR)events on 1989September 29;2001 April 15 and 2005 January 20.This involves examination of hourly raw CR counts of an array of neutron monitors(NMs)spread across different geographical latitudes and longitudes.Using awk script and computer codes implemented in R software,the pressure corrected raw data plots of the NMs were grouped into low-,mid-and high-latitudes.The results show both similarities and differences in the structural patterns of the GLE signals.In an attempt to explain why the CR count during the decay phase of GLEs is always higher than the count before peak,we interpreted all counts prior to the peak as coming from direct solar neutrons and those in the decay phase including the peak as coming from secondary CR neutrons generated by the interactions of primary CRs with the atoms and molecules in the atmosphere.We identified NMs that detected these primary neutrons and found that they are close in longitude.Previous authors seemingly identified these two species as impulsive and gradual events.Although there are a number of unexplained manifestations of GLE signals,some of the results suggest that geomagnetic rigidity effectively determines the intensity of CRs at low-and mid-latitudes.Its impact is apparently insignificant in high-latitude regions.Nevertheless,the results presented should be validated before making any firm statements.Principally,the contributions of the ever-present and intractable CR diurnal anisotropies to GLE signals should be accounted for in future work.

关键词： sun coronal mass ejections(CMEs)-sun flares-sun particle emission

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Parametric Evolution of Power-law Energy Spectra of Energetic Electrons in the Coronal Loops

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Research in Astronomy and Astrophysics 2023年第2期23卷 121-131页

作者： Jian-Fei Tang De-Jin Wu Ling Chen Lei Xu College of Engineering and Design Lishui UniversityLishui 323000China Key Laboratory of Planetary Sciences Purple Mountain ObservatoryCASNanjng 210023China School of Physics and Electronic Information Shangrao Normal UniversityShangrao 334001China

Fast electron beams(FEBs) are one of the main products of various active events and are ubiquitous in solar,space and cosmic plasmas.They reveal themselves in hard X-ray and radio emissions.The observed characteristics of X-ray and radio emissions sensitively depend on the energy distribution of FEBs,which usually have a power-law energy spectrum.As FEBs travel in the solar atmosphere,their energy distribution can considerably vary due to the interaction with ambient plasmas.Tang et al.investigated the evolution of the energy spectrum of the FEBs traveling along a flare loop and discussed the possible effects on associated hard X-ray(HXR) and radio emissions.Considering the ubiquitous coronal loops in active regions,in the present paper,we investigate the parametric evolution of the energy spectra of FEBs when propagating along coronal loops.Here,we take the sunpot atmospheric model as an approximate coronal loop atmosphere model.The results show that the energy loss has an important impact on the cutoff behavior and energy spectra of FEBs when precipitating in a coronal loop with density ratio n_(b)/n_(e)= 0.01.The initially single power-law spectrum with a steepness cutoff can evolve into a more complex double power-law spectrum or two “knees” power-law spectrum with a flattened steepness cutoff behavior or saturation cutoff behavior.Our calculations also demonstrate that the energy spectrum evolution is not obvious if n_(b)/n_(0)= 0.001 as Tang et al.asserted.The present results are helpful for a more comprehensive understanding of the dynamic spectra of HXR and radio emissions from FEBs.

关键词： sun activity-sun flares-sun radio radiation

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Global Energetics of Solar Powerful Events on 2017 September 6

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天文和天体物理学研究:英文版 2023年第9期23卷 180-193页

作者： Dong Li Alexander Warmuth Jincheng Wang Haisheng Zhao Lei Lu Qingmin Zhang Nina Dresing Rami Vainio Christian Palmroos Miikka Paassilta Annamaria Fedeli Marie Dominique Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China State Key Laboratory of Space Weather Chinese Academy of SciencesBeijing 100190China Leibniz-Institut fur Astrophysik Potsdam(AIP) An der Sternwarte 16D-14482 PotsdamGermany Yunnan Observatories Chinese Academyof Sciences.Kunming 650216China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsCASBeijing 00049China Department of Physics and Astronomy University of TurkuTurku 20014Finland Solar-Terrestrial Centre of Excellence/SIDC Royal Observatory of Belgium3 Avenue CirculaireB-1180 UccleBelgium

Solar flares and coronal mass ejections(CMEs)are thought to be the most powerful events on the sun.They can release energy as high as~10^(32)erg in tens of minutes,and also can release solar energetic particles(SEPs)into interplanetary space.We explore global energy budgets of solar major eruptions that occurred on 2017 September 6,including the energy partition of a powerful solar flare,and the energy budget of the accompanying CME and SEPs.In the wavelength range shortward of~222 nm,a major contribution of the flare radiated energy is in the soft X-ray(SXR)0.1-7 nm domain.The flare energy radiated at wavelengths of Lyαand mid-ultraviolet is larger than that radiated in the extreme ultraviolet wavelengths,but it is much less than that radiated in the SxR waveband.The total flare radiated energy could be comparable to the thermal and nonthermal energies.The energies carried by the major flare and its accompanying CME are roughly equal,and they are both powered by the magnetic free energy in the NOAA AR 12673.Moreover,the CME is efficient in accelerating SEPs,and the prompt component(whether it comes from the solar flare or the CME)contributes only a negligible fraction.

关键词： sun flares-sun magnetic fields-sun coronal mass ejections(CMEs)

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Change Ratios of Magnetic Helicity and Magnetic Free Energy During Major Solar flares

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天文和天体物理学研究:英文版 2023年第9期23卷 309-321页

作者： Quan Wang Mei Zhang Shangbin Yang Xiao Yang Xiaoshuai Zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China

Magnetic helicity is an important concept in solar physics,with a number of theoretical statements pointing out the important role of magnetic helicity in solar flares and coronal mass ejections(CMEs).Here we construct a sample of 47 solar flares,which contains 18 no-CME-associated confined flares and 29 CME-associated eruptive flares.We calculate the change ratios of magnetic helicity and magnetic free energy before and after these 47 flares.Our calculations show that the change ratios of magnetic helicity and magnetic free energy show distinct different distributions in confined flares and eruptive flares.The median value of the change ratios of magnetic helicity in confined flares is-0.8%,while this number is-14.5%for eruptive flares.For the magnetic free energy,the median value of the change ratios is-4.3%for confined flares,whereas this number is-14.6%for eruptive flares.This statistical result,using observational data,is well consistent with the theoretical understandings that magnetic helicity is approximately conserved in the magnetic reconnection,as shown by confined flares,and the CMEs take away magnetic helicity from the corona,as shown by eruptive flares.

关键词： sun corona-sun flares-sun magnetic fields

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X-Ray Fine Structure of a Limb Solar Flare Revealed by Insight-HXMT,RHESSI and Fermi

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Research in Astronomy and Astrophysics 2022年第5期22卷 47-55页

作者： Ping Zhang Wei Wang Yang Su Shuangnan Zhang Liming Song Fangjun Lu Shu Zhang Department of Physics and Technology Wuhan UniversityWuhan 430072China WHU-NAOC Joint Center for Astronomy Wuhan UniversityWuhan 430072China Purple Mountain Observatory of the Chinese Academy of Sciences Nanjing 210023China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

We conduct a detailed analysis of an M1.3 limb flare occurring on 2017 July 3,which have the X-ray observations recorded by multiple hard X-ray telescopes,including Hard X-ray Modulation Telescope(Insight-HXMT),Ramaty High Energy Solar Spectroscopic Imager(RHESSI),and the Fermi Gamma-ray Space Telescope(Fermi).Joint analysis has also used the extreme ultraviolet(EUV)imaging data from the Atmospheric Imaging Assembly(AIA)aboard the Solar Dynamic Observatory.The hard X-ray spectral and imaging evolution suggest a lower corona source,and the non-thermal broken power law distribution has a rather low break energy~15 keV.The EUV imaging shows a rather stable plasma configuration before the hard X-ray peak phase,and accompanied by a filament eruption during the hard X-ray flare peak phase.Hard X-ray image reconstruction from RHESSI data only shows one foot point source.We also determined the DEM for the peak phase by SDO/AIA data.The integrated EM beyond 10 MK at foot point onset after the peak phase,while the>10 MK source around reconnection site began to fade.The evolution of EM and hard X-ray source supports lower corona plasma heating after non-thermal energy dissipation.The combination of hard X-ray spectra and images during the limb flare provides the understanding on the interchange of non-thermal and thermal energies,and relation between lower corona heating and the upper corona instability.

关键词： sun flares-sun corona-sun X-rays-gamma-rays-plasmas-radiation mechanisms non-thermal-radiation mechanisms thermal

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A Revised Graduated Cylindrical Shell Model and its Application to a Prominence Eruption

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Research in Astronomy and Astrophysics 2023年第12期23卷 63-72页

作者： Qing-Min Zhang Zhen-Yong Hou Xian-Yong Bai Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryNanjing 210023China Yunnan Key Laboratory of the Solar Physics and Space Science Kunming 650216China School of Earth and Space Sciences Peking UniversityBeijing 100871China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Solar Activity and Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China

In this paper,the well-known graduated cylindrical shell(GCS)model is slightly revised by introducing longitudinal and latitudinal deflections of prominences originating from active regions(ARs).Subsequently,it is applied to the three-dimensional(3D)reconstruction of an eruptive prominence in AR 13110,which produced an M1.7 class flare and a fast coronal mass ejection(CME)on 2022 September 23.It is revealed that the prominence undergoes acceleration from~246 to~708 km s^(-1).Meanwhile,the prominence experiences southward deflection by 15°±1°without longitudinal deflection,suggesting that the prominence erupts non-radially.Southward deflections of the prominence and associated CME are consistent,validating the results of fitting using the revised GCS model.Besides,the true speed of the CME is calculated to be 1637±15 km s^(-1),which is~2.3 times higher than that of prominence.This is indicative of continuing acceleration of the prominence during which flare magnetic reconnection reaches maximum beneath the erupting prominence.Hence,the reconstruction using the revised GCS model could successfully track a prominence in its early phase of evolution,including acceleration and deflection.

关键词： sun flares-sun filaments-prominences-sun coronal mass ejections(CMEs)

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Breaking of Large-Scale Filament due to Magnetic Reconnection and Consequent Partial Eruption

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天文和天体物理学研究:英文版 2023年第9期23卷 194-206页

作者： Kaifeng Kang Yang Guo Yan Li Jingxing Wang Jun Lin Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China Yunnan Key Laboratory of Solar Physics and Space Science Kunming 650216China School of Astronomy and Space Science and Key Laboratory for Modern Astronomy and Astrophysics Nanjing UniversityNanjing 210023China

Following our previous work,we studied the partial eruption of a large-scale horse-shoe-like filament that had beenobserved in a decaying active region on the solar disk for more than 4.5 days.The filament became active after itwas broken into two pieces,P1 and P2 seen in Hα,by magnetic reconnection between the magnetic field around itand that of a newly emerging active region nearby.P1 eventually erupted 13 hr after the breaking and escaped fromthe sun,developing to a fast coronal mass ejection,and P2 stayed.But the mass in P1 falling down to P2 in theeruption suggests that the global magnetic fields over P1 and P2 were still connected to each other prior to theeruption.The reconnection process breaking the filament occurred outside the filament,and P1 and P2 were locatedalmost at the same altitude,so the fashion of the filament partial eruption studied here differs from that of the“double-decker model”and that of reconnection inside the filament.Analyzing the decay indices of thebackground fields above P1 and P2,n_(1)and n_(2),showed that the altitude where n_(1)exceeds the critical value of n_(c)=1.5 for the loss of equilibrium or the torus instability is lower than that where n_(2)>nc,and that n_(1)>n_(2) alwaysholds at all altitudes.Combining this fact with that the eruption occurred 13 hr after filament was broken byreconnection,we conclude that the eruption of P1 was triggered by the loss of equilibrium or the torus instability inthe configuration,and magnetic reconnection breaking the filament helped weaken the confinement of thebackground field on P1,allowing P1 to erupt.Detailed features of the eruption and the corresponding physicalscenario were also discussed.

关键词： sun activity-sun filaments-prominences-sun coronal mass ejections(CMEs)-sun flares-sun magnetic fields

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Eruption of an Active-Region Filament Driven by an Emerging Bipole

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Chinese Journal of Astronomy and Astrophysics 2007年第1期7卷 129-140页

作者： Yun-Chun Jiang Yuan-Deng Shen Jing-Xiu Wang National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Kunming 650011 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

A section of an S-shaped filament underwent an eruption in a sigmoidal active region （AR 8027） with S-shaped coronal structure, which was clearly driven by a bipole emerging below the NW end of the filament. The bipole with two separating poles showed typical characteristics of emerging flux region （EFR） and its axis rotated counterclockwise. Two canceiling magnetic features （CMFs） were formed between the two poles and adjacent flux with opposite polarity and substantial flux cancellation occurred in them. Along with the bipole emergence the filament was strongly disturbed. Just before the filament eruption, two X-ray loops overlying the filament brightened, an axial X-ray structure and then a cusp structure appeared. During the eruption first the whole filament rose and then its SE end broke away from the chromosphere, while its NW end remained stationary. Helical structure and motion were observed in the filament body and downward mass motion in the two ends. After the eruption, a major part of the filament remained and slowly returned to quiescence, and an X-ray arcade and an axial structure formed. These observations suggest that the eruption resuited from the interaction between the bipole and the overlying loops. We provide evidence that steady photospheric reconnection between their footprints took place in the two CMFs during the bipole emergence.

关键词： sun： filaments-sun flares-sun magnetic fields-sun corona-sun X-rays

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Relationship between CME velocities and X-ray fluxes of associated flares

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Chinese Journal of Astronomy and Astrophysics 2009年第4期9卷 470-474页

作者： An-Qin Chen Wei-Guo Zong National Center for Space Weather China Meteorological Administration Beijing 100081 China State Key Laboratory of Space Weather Chinese Academy of Sciences Beijing 100080 China

Coronal mass ejection （CME） velocities have been studied over recent decades. We present a statistical analysis of the relationship between CME velocities and X-ray fluxes of the associated flares. We study two types of CMEs. One is the FL type associated only with flares, while the other is the intermediate type associated with both filament eruptions and flares. It is found that the velocities of the FL type CMEs are strongly correlated with both the peak and the time-integrated X-ray fluxes of the associated flares. However, the correlations between the intermediate type CME velocities and the corre- sponding two parameters are poor. It is also found that the correlation between the CME velocities and the peak X-ray fluxes is stronger than that between the CME velocities and the time-integrated X-ray fluxes of the associated flares.

关键词： sun coronal mass ejections （CMEs）-sun flares-sun filaments

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