Magnetic Field Evolution Leading to Solar Flares II. Cases with High Magnetic Shear and Flare-Related Shear Change

[摘要] FollowingPaperIinwhichweconsideredfivesolarflares,wehaveselectedanotherthreesolarflaresgreaterthanGOESX-rayclassM/Hαimportance1.Thethreeactiveregionsdiscussedherearecharacterizedbyhighmagneticshear.WeinvestigatedthespatialrelationshipsamongHαflareribbons,softX-ray(SXR)flareloops,andmagneticconfigurationsforthethreeflaresproducedintheseactiveregions.OurresultsshowthatonlyoneofthesethreeflaressatisfiesthesufficientconditionsforaflaretooccurproposedbyHagyard(1990,AAA052.075.047).Wealsodiscussthemagneticshearchangesaroundtheflaringtimeonlyalongtheneutrallinesassociatedwiththestudiedflaresandoverthewholeflaringarea.Theflare-relatedchangesontheneutrallinearesmall(2°–4°)andtheassociationofthesechangeswiththeflaresisnotconclusive.Theaverageshearintheflaringareasoftheflaresassociatedwithhighsheardecreasessignificantlyaftertheflaresanditmaybeabetterparametertocharacterizetheflare-relatedshearchangesinsuchcases.

[学科分类] 天文学(综合)

[关键词] "Sun: flares";"Sun: magnetic fields";"Sun: X-rays"