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1、Thequantitativeanalysisofthespiral chiralityofpenumbralfilament1HelicityThinkshoponSolarPhysics,Oct.2013,BeijingLiuJ.H.,SuJ.T.etal.ShijiazhuangUniversityKeyLaboratoryofSolarActivity,NAOCOutlines1.Backgroundofpenumbralfilament(fibrals)andScrewpinchinstability2
2、.Unwindingandtwistchangeinpenumbralfilaments(Suetal.2010,ApJ,710,170);3.Screwpinchinstabilityandpenumbralfilamentscharality;4.ScrewpinchinstabilityandaC2.6flare.1.Backgroundofpenumbralfilaments(fibrals)Uncombedmodel:Ittakesthepenumbraasacollectionofhorizontal
3、fluxtubesinamoreverticalbackgroundfield.(Solanki&Motavon1993).Gapmodel:Afield-freemodelwhichtakesthefilamentsasthenon-magnetizedconvectinghotgasprotrudingintothebackgroundofpotentialmagneticfields.(SpruitandScharmer2006;ScharmerandSpruit2006).Bystudyingtheexp
4、asion,unwinding,shrinking,twistingmotionofthepenumbralfilament,Suetal.considerthatthepenumbralfilamentsarethetwistedmagneticfluxtubesinnature.(Suetal.2010)Therearetwoschematicmodelsareintenselystudiedregardingtheoriginofthepenumbralfilaments.4pitch:thedistanc
5、einwhichthefieldlinemakesonerevolutionaroundthefluxtube,isRistheradiusofthefluxtubeandLisitslength.(Priest1984,Ryutovaetal.2008)“screwpinch”configurationLong,magneticcylindricalfluxtubesaresubjecttohelicalinstabilities,andamagneticfluxtubewithbothazimuthaland
6、axialcomponentstwistsintoakinkedhelicalshape.BackgroundofScrewpinchinstability5Saftyfactor:ThescrewpinchinstabilityturnsonwhenthesafetyfactorisScrewpinchinstability6(h/R)>2.62,themagneticfieldcomponentspreservetheirinitialdirectionandchirality.2.1.63<(h/R)<2.
7、62,theaxialmagneticfieldreversesbutthechiralityofthefilamentremainsthesame.3.1.14<(h/R)1.63,theaxialmagneticfieldreversalisaccompaniedbyreversedchirality.Forthekinkmodem=1:Ryutova,Berger&Title2008Model:7ConsideringthechiralityOnlyandforthekinkmodem=1:(h/R)>1.
8、63,thechiralityofthefilamentremainsthesame.1.14<(h/R)<1.63,thechiralityofthefilamentreverse.(h/R)<1.14,verystrongtwist,willleadtodisruptionofthefilament.2.Unwindingandtwistchangeinpenumbr
