Magnetosphere response to the IMF turning from north to south

(整期优先)网络出版时间:2019-01-11
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Inthispaper,theSpaceWeatherModelingFramework(SWMF)isusedtosimulatethereal-timeresponseofthemagnetospheretoasolarwindeventonJune5,1998,inwhichtheinterplanetarymagneticfieldshifteditsdirectionfromnorthtosouth.Sincemostcurrentmodelsdonottakeintoaccountconvectiveeffectsoftheinnermagnetosphere,wefirststudytheimportanceofRiceConvectionModel(RCM)intheglobalmodel.Wethenfocusonthefollowingfouraspectsofthemagnetosphere’sresponse:themagnetosphere’sdensitydistribution,thestructureofitsmagneticfieldlines,theareaofthepolarcapboundary,andthecorrespondingionosphericcurrentchange.Wefindthat(1)whentheIMFchangesfromnorthtosouthinthisevent,highmagnetosheathdensityisobservedtoflowdownstreamalongthemagnetopausewiththesolarwind;low-latitudereconnectionatdaysideoccursunderthesouthwardIMF,whilethemagneticfieldlinesinthetaillobecaudal,causedbythenightsidehighlatitudereconnection,extendintotheinterplanetaryspace.Openmagneticfieldlinesexistsimultaneouslyatbothhighandlowlatitudesatthemagnetopause;(2)theareaofthepolarcapisobviouslyincreasediftheIMFturnsfromthenorthtothesouth;thisobservationishighlyconsistentwithempiricalobservations;(3)theionosphericfieldaligncurrentinthenorthernhemisphereisstrongerthaninthesouthernhemisphereandalsoincreasesastheIMFchangesfromnorthtosouth.SWMFwiththeRiceConvectioneffectprovidesreliablemodelingofthemagnetosphericandionosphericresponsetothissolarwindvariation.