TheCoronalGlobalEvolutionaryModel(CGEM):CurrentStatus,FutureApplications

GeorgeH.Fisher1,MarcDeRosa2,ToddHoeksema3,andtheCGEMTeam1,2,3

1SpaceSciencesLab,UCBerkeley2LockheedMartinSpaceAstrophysicsLaboratory

3StanfordUniversity

CGEMisfundedbyNSFawardAGS-1321474toUCBerkeley,NASAawardNNX13AJ96G toLockheed,andNASAawardNNX13AK39GtoStanford.

OverviewofthetwotalksonCGEM

• GeorgeFisher(UCB)willdiscusstheoverallgoalandcurrentstatusoftheCGEMproject anddiscussionofitsfutureapplications,followedby10minutesforquestionsanddiscussion.

• MariaKazachenko (UCB)willdiscusstheimportanceofvectormagneticfieldsinquantitativestudiesofsolarevolution.Thiswillbefollowedby10minutesforquestionsanddiscussion.

TheGoalofCGEMThegoalofCGEMistodevelopamodeloftheevolvingmagneticfieldinthesolarcorona,drivenbySDO/HMIphotospheric magneticfieldandDopplervelocitydata.Magneticevolutioniscomputedusingthemagnetofrictional(MF)approximation,drivenbyelectricfieldsdeterminedfromtheSDO/HMIdataatthephotosphere.TheCGEMmodelassumessphericalgeometry,andcanemployeitherhigh-resolutionactive-regionscaledomains,orlower-resolutionfullyglobalmodels.OutputfromMFmodelscanthenbeusedtodriveMHDmodelsofthecoronaorheliosphere ifdesired.

AnOverviewofCGEM:Fisheretal.,SpaceWeatherVol.13,(6),pp.369-373,2015.

CGEMURL:http://cgem.ssl.berkeley.edu

SixDeliverablesAreNeededtoAchievetheCGEMGoal

• D1:AMagnetofrictional (MF)ModeloftheSun’scoronalmagneticfield

• D2:AGlobalFluxTransport(FT)ModelusedforunobservedpartsoftheSun’sphotosphere

• D3:ElectricFieldsatthePhotospherederivedfromHMImagneticfieldandDopplerdata

• D4:Enhanceddataproducts(forinputtoD3)andforotherscientificandspace-weatherpurposes

• D5:AnMHDmodelofthecoronainactiveregions,initializedbytheMFmodel,tostudyeruptingmagneticgeometries

• D6:AGlobalCoronalMHDmodeldrivenbytheglobalMForactive-regionMHDmodels

CGEMWorkflowDiagram1

D3

D4

D4

D4

CGEMWorkflowDiagram2D3

D2

D1 D5

D1 D6

ExecutiveSummaryofCGEMProgressYears1-4:

• D1(MFModel):Codewritten,workinginbothlocalizedandglobalgeometries.CCMCdeliverydiscussionsstarted.

• D2(FTModel):Codewritten,working,startingCCMCdeliverydiscussionsinconjunctionwithMFmodel.

• D3(ElectricFieldInversions):Codewritten,working,deliveredtoJSOC.Codeisanopen-sourcefortran library,writtenforabroadspectrumofuses,includingdataanalysisandforuseinMHDcodes.

• D4(EnhancedDataProducts)Codeswritten,working,mostdeliveredtoJSOC.OnepieceofIDLcodestillneedstobeportedtotheJSOC.

• D5(ActiveRegionModels)Codewritten,working,sourcecodereleasedtopublic

• D6(Heliospheric Models)Codewritten,working,deliveredtoJSOC

D1:MFmodelofAR11158(sphericalwedgerun,6days,720HMIvectormagnetograms)

• MFmodelbalancestheLorentzforceagainstafictitiousfrictionalforce

• MFmodelevolvesvectorpotentialAtocomputemagneticfieldB.

• MFmodelusesstaggered,Yeegridinsphericalcoordinates.

• MFmodelisdrivenfromthephotospherebyvaluesoftheelectricfieldE.

• MFmodelnowworkinginbothsphericalwedgeandglobalsphericalconfigurations.

• At512processorsonPleidescluster,computetimeaboutequaltoelapsedsolartime

Br at4Mm Br at40Mm

BT BP

D2:SurfaceFluxTransportModel

• GlobalmodelforBr• Electricfield-basedformalism,usingstaggeredYeegrid,consistent

withMFmodel(D1)andElectricFieldInversionsoftware(D3).Theelectricfieldformalismprovidesmorephysicalinformationthanpreviousfluxtransportmodels

• Canimbedelectricfieldinversions(D3)fromSHARPregionsintoglobalsolutions

Br

∇× E

D3:ElectricFieldsatphotospherefromHMImagneticandvelocitydatausingPDFImethod

• ThePDFImethodisdescribedandvalidatedinKazachenko etal(2014)foracentered,Cartesiangrid.

• Wehavesincere-writtenthesoftwareinsphericalcoordinates,usingthestaggeredYeegrid(compatiblewithD1,D2deliverables)

• PDFISoftwarenowwrittenentirelyinFortran,deliveredtoJSOCforsphericalwedgegeometry.6daysofSHARPdataprocessedin~2hr onamacbook pro

• ElectricfieldscanbeusedforindependentscienceinvestigationsaswellasfortheCGEMmodel-drivinggoals.

Magneticfield,ElectricfieldandPoynting fluxvectorsincoreofAR11158(seeKazachenko etal.2015).

GeneralUsesoftheD3deliverablesoftware(PDFI_SS)beyondCGEM:

• Electricfieldinversionsoftwareisnowwrittenasageneralpurpose,open-sourcefortranlibrary.URL:http://cgem.ssl.berkeley.edu/cgi-bin/cgem/PDFI_SS/index

• ScientificStudiesinvolvingPoynting fluxandhelicity injection

• Dataassimilation:Subroutinesfor“nudging”MHDorSMFsolutionstouseobservedmagneticfielddataatphotosphere.

D4:EnhancedDataProducts• Sub-pixelco-registrationof

magneticfieldandDopplerdatafromHMI

• Correctedmagneticazimuthvaluesusingobservedtimeevolution

• FLCTderivedhorizontalvelocities

• PILvaluesofDopplervelocity,correctedforconvectiveblue-shift

• Lorentzforcesinflaringactiveregions

• High-cadence(135s)vectormagneticfielddata(seeSunetal.2017,ApJ 839,67.)

ThisFigureshowstheverticalLorentzforcetransientderivedfromhighcadencevectormagneticfielddataforAR11158.

GlobalCGEMmodel:AnearlyresultillustratingtheworkflowbetweenD4,D3,D2andD1:

• 33-dayrunofGMFusingPDFIelectricfieldsolutionsforAR11158fordays1-6,SFTmodelforEeverywhereelseandgloballyafterthe6daysofdataingestion

• Lowresolutionmode256x104inlon,latand128inrbetween1.0and2.28R_S.

• Simulationrunson416-processornodes(SandyBridge)onPleides (NASAAmes)atroughly130xfasterthansolartime

• Note“seam”artifactsinmagneticfieldwherePDFI_SSresultsareimbeddedintoFTMatphotosphere.ThisisduetoinconsistenciesinboundaryconditionsbetweenFTMandPDFI_SS;canbefixedbyaddingcurl-freesolutiontoPDFI_SSthatmatchesFTMatboundary.

GlobalCGEMmodel:coronalfieldappearanceusingCheung-DeRosa J2 emissivityat4simulationtimes:

D5:MHDmodelsofunstableARconfigurations,startingfromMFmodeloutput

• Weuseasimplifiedzero-betaversionoftheRADMHDcodetoevolveunstablemagneticconfigurationsfoundwiththeMFmodel.

• RADMHDSourcecodeavailabletothepublicwithanopen-sourcelicense.

• OutputfromCGEMMHDrunswillbepostedontheJSOCorCGEMwebsites.

• RADMHDsimulationswillalsobeusedtoexploretheeffectsofadditionalphysicsbeyondtheMForzero-betaMHDapproximations.

Comparisonofsyntheticemission(Cheung&DeRosa 2012)computedwithRADMHDcodewithobservationsofthecoronainAR11158

D6:Large-scaleGlobalCoronalMHD

• Low-resolutionglobalMHDmodelsofthecoronaarenowmadeavailabledailyontheJSOCwebsite.

• TheglobalMHDmodelwillbeextendedto1AUintheintermediatefuture.

• TheinterfacebetweentheMFandactive-regionscaleMHDmodelsandtheglobalMHDmodelisnowbeingdefined.

Afewframesfromasimulationfrom1.2RSto50RS overaperiodof10hours.Domainshownfrom1.2to5RS.

PublicationsandPresentationsfundedbyCGEM

• 16publicationsduringYears1-4werefundedbytheNASAandNSFCGEMawards.

• Over45publicpresentationsontheCGEMprojectweremadeduringYears1-4

• Linkstothepublications,andthedescriptionsofthepresentationscanbefoundontheCGEMwebsite,http://cgem.ssl.berkeley.edu .ThewebsitealsohaslinkstoalloftheprogressreportsforCGEM.

Delivery,Documentation,andValidation

• DiscussionshavebegunwithPeterMacNeiceregardingdeliveryoftheD1andD2modelstotheCCMC.WorkingversionsofD3andD6havebeendeliveredtotheJSOC.MostcomponentsofD4arenowrunningattheJSOC.D5sourcecodereleasedtocommunityasopen-sourcesoftware;simulationresultstobepostedonJSOCorCGEMwebsites.

• DocumentationforD1,D2deliverablesisinprogress.D3sourcecodeincludesanoverviewplusdetailsofprogramminginterfacewitheachsubroutine.DocumentationforLorentz-forcediagnostic(partofD4)hasbeenpublished.DocumentationforD5,D6inprogress.

• ValidationofD1,D2havebeendoneforsimpleknowntestcases(D1)andcomparisonwithotherfluxtransportcodes(D2).ValidationofD3isperformedbycomparingelectricfieldinversionsfromknownelectricfieldsinMHDsimulations.D4validationisdonebycross-checksandself-consistencycheckswiththeHMIdata.D5,D6validationdonewithknownMHDtestcases.

• End-to-endvalidationofCGEMmodelwillentailacomparisonbetweenemissivityproxiesandknowncoronalemissiondiagnostics,pluschecksbetweenthepredictedversusobservedtimesandlocationsofmagneticeruptions.

D4D4

D4

D3

D3

D2

D1

D1

D5

D6

WorkplannedforYear5• CompletetransitionofallD4softwaretoaformwhichcan

berunautomaticallyattheJSOC• More“campaign”studiesusingmoreactiveregions

observedbySDO• CGEMsimulationsusinglarge-scaleFOVregionsoftheSun

(someearlyresultsshowninthispresentation)• BeginstudiesintegratingglobalMFmodelwithglobal

coronal/heliospheric MHDmodel• ImprovedtechniquesforvisualizingsphericalMFandMHD

data(someearlyresultsshowninthispresentation)• Moredocumentationofthedeliverablemodels• CompleteandvalidatethedeliverablesforJSOCandCCMC

Summary:Significantresultsandkeyoutcomes

• Keyoutcome:WehavesuccessfullyachievedourgoalofbuildingatemporallyevolvingmodeloftheSun’scoronalmagneticfieldinsphericalgeometry,drivenbyelectricfieldsatthephotosphere. Whilemuchremainstobedonetocompletetheproject,wenowknowthatourmodelgoalispossible,practical,andiswellonitswaytosuccessfulcompletion.

• Majoraccomplishmentsweremadeforall6ofourdeliverables.

• Wewelcomecollaborationswiththeotherstrategiccapabilityefforts.