简介: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.
简介:
简介:WepresentpreliminaryresultsofanewglobalMagnetohydrodynamics(MHD)simulationmodeloftheJovianmagnetosphere.ThemodelincorporatesmassloadingfromJupiter'ssatelliteIo,theplanet'sfastcorotation,andelectrostaticcouplingbetweenitsmagnetosphereandionosphere(M-Icoupling).ThebasicconfigurationoftheJovianmagnetosphereincludingtheequatorialplasmaflowpattern,thecorotationenforcementcurrentsystem,andthefieldalignedcurrents(FACs)intheionospherearepresentedunderanantiparallelinterplanetarymagneticfield(IMF)condition.Thesimulationmodelresultsforequatorialdensityandpressureprofilesareconsistentwithresultsfromdata-basedempiricalmodels.ItisalsofoundthattherearesimilaritiesbetweentheFACsdistributionintheionosphereandtheobservedaurorafeatures,showingthepotentialapplicationofthesimpleionosphericmodeltothecomplicatedM-Icoupling.ThismodelwillhelpdeepenourunderstandingoftheglobaldynamicsoftheJovianmagnetosphere.
简介:Whistler-modechoruswavesareregardedasanimportantaccelerationmechanismcontributingtotheformationofrelativisticandultra-relativisticelectronsintheJovianradiationbelts.QuantitativedeterminationofthechoruswavedrivenelectronscatteringeffectintheJovianmagnetosphererequiresdetailedinformationofbothambientmagneticfieldandplasmadensityandwavespectralproperty,whichhowevercannotbealwaysreadilyacquiredfromobservationsofexistedmissionstoJupiter.WethereforeperformacomprehensiveanalysisofthesensitivityofchorusinducedelectronscatteringratestoambientmagnetosphericandwaveparametersintheJovianradiationbeltstoelaboratetowhichextentthediffusioncoefficientsdependonanumberofkeyinputparameters.Itisfoundthatquasi-linearelectronscatteringratesbychoruscanbestronglyaffectedbytheambientmagneticfieldintensity,thewavelatitudinalcoverage,andthepeakfrequencyandbandwidthofthewavespectraldistributionintheJovianmagnetosphere,whiletheyonlyrelyslightlyonthebackgroundplasmadensityprofileandthepeakwavenormalangle,especiallywhenthewaveemissionsareconfinedatlowerlatitudes.Giventhechoruswaveamplitude,chorusinducedelectronscatteringratesstronglydependonJovianL-shelltoexhibitatendencyapproximatelyproportionaltoLJ3.OurcomprehensiveanalysisexplicitlydemonstratestheimportanceofreliableinformationofboththeambientmagnetosphericstateandwavedistributionpropertytounderstandingthedynamicelectronevolutionintheJovianradiationbeltsandthereforehasimplicationsforfuturemissionplanningtoexploretheextremeparticleradiationenvironmentofJupiteranditssatellites.