Validation of a scaling law for the coronal magnetic field strength and loop length of solar and stellar flares

Publications of the Astronomical Society of Japan

Shibata, Kazunari²  Watanabe, Kyoko¹  Namekata, Kosuke³  Asai, Ayumi²  Sakaue, Takahito³ 

[1] National Defense Academy of Japan, 1-10-20 Hashirimizu, Yokosuka, Kanagawa 239-8686, Japan;Kwasan and Hida Observatories, Kyoto University, 17 Ohmine-cho Kita Kazan, Yamashina-ku, Kyoto, Kyoto 607-8471, Japan;Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, Kyoto 606-8502, Japan

关键词: "stars: flare";    "Sun: corona";    "Sun: flares";    "Sun: magnetic fields";   

DOI  :  10.1093/pasj/psw111

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

ShibataandYokoyama(1999,ApJ,526,L49; 2002,ApJ,577,422)proposedamethodofestimatingthecoronalmagneticfieldstrength(B)andmagneticlooplength(L)ofsolarandstellarflares,onthebasisofmagnetohydrodynamicsimulationsofthemagneticreconnectionmodel.UsingthescalinglawprovidedbyShibataandYokoyama(1999,ApJ,526,L49; 2002,ApJ,577,422),weobtainBandLasfunctionsoftheemissionmeasure(EM=n2L3)andtemperature(T)attheflarepeak.Here,nisthecoronalelectrondensityoftheflares.ThisscalinglawenablestheestimationofBandLforunresolvedstellarflaresfromtheobservablephysicalquantitiesEMandT,whichishelpfulforstudyingstellarsurfaceactivities.Toapplythisscalinglawtostellarflares,wediscussitsvalidityforspatiallyresolvedsolarflares.QuantitiesEMandTarecalculatedfromGOES(GeostationaryOperationalEnvironmentalSatellite)softX-rayfluxdata,andBandLaretheoreticallyestimatedusingthescalinglaw.Forthesameflareevents,BandLwerealsoobservationallyestimatedwithimagestakenbytheSolarDynamicsObservatory(SDO)/HelioseismicandMagneticImager(HMI)MagnetogramandAtmosphericImagingAssembly(AIA)94 Åpassband.Asexpected,apositivecorrelationwasfoundbetweenthetheoreticallyandobservationallyestimatedvalues.Weinterpretthisresultasindirectevidencethatflaresarecausedbymagneticreconnection.Moreover,thisanalysismakesusconfidentaboutthevalidityofapplyingthisscalinglawtostellarflaresaswellassolarflares.

【 授权许可】

Unknown