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TheGreatAugust1972Heliospheric Disturbance:WhatWeKnowNowCriticalChallengesandProgress
HourlyaveragedX-rayIntensityforMcMath Region,11976,Aug1972
DeloresKnipp, UniversityofColorado,Boulder&HAONCAR;BrianFraser,CentreforSpacePhysics,UniversityofNewcastle;MargaretShea &DonSmartRetiredUSAFResearchLaboratory
•Knipp, D. J., et al. (2018), On the Little-Known Consequences of the 4 August 1972 Ultra-Fast Coronal Mass Ejecta: •Facts, Commentary and Call to Action, Space Weather, 16. https://doi.org/10.1029/2018SW002024
25 1 167
McMath Region,11976,Ca-II
3AugOhshio (1974)BASS2000, Paris Observatory, PSL
Zirin andTanaka(1973)
McMath11976MagnetogramBBSO,Aug1972
Overview
• Oneofthemostintenseintervalsofsolar/geospace activityduringthespaceage
• Extraordinaryeffectsingeospace
SolaractivitySEPs&GLEGICs&dB/dt
• Newinsights• Driversof
Carrington-classstorms
McMath Region119764Aug1972X-rayOSO5UniversityCollegeLeicesterUniv
• Active RegionSingle large penumbra; Delta configuration1200 millionths of hemisphere Light bridge
• Extraordinary solar flares2 Aug: (2), X class & WLF4 Aug: (1), X-20 + Gamma-rays7 Aug: (1) X class & WLF
• Flare level 4 Aug 0630 UT– 3B H-alpha– X-ray – LDE flare – Combined Flare Index = 17
InitialPerspectives
BASS2000, Paris Observatory, PSL
Zirin andTanaka(1973)BBSOKoyama(1972)Tokyo
AtEarth:4August1972
Hakura (1974)
• RadioPropagationDisturbance&Blackout• Dayside&thenPolarCap
• Forbush Decrease
• RapidRiseofSEPs• ThenonsetofGroundLevelEvent(GLE24)• Spacecraftsolarpanelsdeteriorated• Sensorsoverwhelmedwithparticles• Long-lastingozonedepletion
• ExtremeForbush Decrease
• SuddenStormCommencements&ExtraordinarySuddenImpulse
X-rayFlare(reconstructed)
Ohshio (1974)
~X20flare
• Space-basedSOLRAD9&10X-raydetectorsSaturatedatX5.1
• ~X-20flare,LongDurationEvent,>16hr
• Radioburstsalsoobserved;indicativeofplasmacloudmotion
• 3hr daysideradioblackout
• Filament~0.6RS disappears
• LargestForbush Decreaseinlast6solarcycles-28%
SEPs(reconstructed)
Jiggens etal.(2014)
• ThemostintensefluxoflowandmoderateenergySEPsinthespace-age
• SignificantenhancementsaheadofCMEs--EnergeticStormParticles
• SolarPanelsonspacecraftlost5%ofpowergenerationcapabilityinthreedays
SolarWind(reconstructed)fromPrognoz &Prognoz 2
• SignificantsolarwinddensityenhancementsfrompreviousCMEs• Preconditioningofgeospace?
• Path-clearingeventspriortoshockarrivalat2054UTon4August
• FastestCMEonrecord—14.6hrsto1AU• AverageCMEtransitspeed:2850km/s
• Shock&structureswithinsheath? Vaisberg&Zastenker, (1976),Zastenker etal.(1978)
HourlyAverageSolarWindPlasmaParameters
•Knipp,D. J., et al. (2018), Space Weather, 16. https://doi.org/10.1029/2018SW002024
IMFatGeosynchronousOrbit
Cahill&Skillman(1977)
Near-noonMagnetosheathField
• ATS5(GEOS/C)inthemagnetosheath• Clearmagnetopausecompression
• RapidIMFfluctuations• InsheathaheadofICME?
• Extremesouthwardfield• -300nT insheath
• -75– -100nT inSW
SI
SSC
Sheathfield(behindIPshock,aheadofICME)
•Knipp,D. J., et al. (2018), Space Weather, 16. https://doi.org/10.1029/2018SW002024
IndicesfromGroundMeasurements
Akasofu (1974)
AfterSSC
• AE>1500nT (hr avg)• |AU|>|AL|
• Dst Index:- 125nT
• ExtremeASYIndex>thanDst
SI
SSC
4-5AugShockShockShock?&ICME1/2&ICME3&ICME4
4 5
High&Mid-latitudeGroundSuddenImpluse dB/dt
• 2238-2242UTLargevoltageswingsinnorthern tierUSstates.
• TheManitobaHydroCompanyrecorded120MWdrops inpowersupplied toMinnesotainonlyafewminutes.
• OutageontheL4(AT&T)cableintheUSMidweststates• Inducedelectricfieldof7.0V/km,exceededshutdown
threshold forhighcurrent,accompaniedmagneticfieldvariations(dB/dt)of~800nT/minat2240-2242UT(thetimeoftheL4outage).
• dB/dT =2000nT/min innorthernCanada
• Newfoundland, Canada,GICsactivatedprotectiverelaysmanytimeson4-5August.
• StrongGICeffectsreported inOhioandMarylandAlbertson &Thorson, (1974),
BotelerandJansen vanBeek (1999)
• SSC2054UT
• SI2038-2242UT
• 168nT/minManila,Philippines• NeardawnLocalTime• 7deg MLAT
• SubsequentGiantPulsations
Low-LatitudeGroundMagneticPerturbations
Salcedo(1973)
•Knipp,D. J., et al. (2018), Space Weather, 16. https://doi.org/10.1029/2018SW002024
HaiPhong MineField‘swept’byaSolarMagneticStormon4August1972
ByUnitedStatesNavyphotograph - ScannedfromMelia,TamaraMoser,"DamntheTorpedoes":AShortHistoryofU.S.NavyMineCountermeasures,1777-1991,Washington,D.C.:NavalHistoricalCenter,1991, ISBN0-945274-07-6,p.108.,PublicDomain,https://commons.wikimedia.org/w/index.php?curid=32761410
Mineexplosion duringSweepingHaiphongHarbor1973
“During the first few weeks of August, a series of extremely strong solar flares caused a fluctuation of the magnetic fields, in and around, South East Asia. The resulting chain of events caused the premature detonation of over 4,000 magnetically sensitive DSTs (Destructor mines)”Gonzales, https://www.angelo.edu/content/files/21974-a
“…theHaiPhong Destructor(mine)FieldwasactuallysweptbyasolarmagneticstorminAugustof1972.”Hartmann&Truver (1991)
ProgressinUnderstandingExtremeShocks&CMEs(1)
• Tousey (1973): CoronalTransients(CMEs)observedbyOSO-7
Agrawal, etal.(1974)
• Agrawaletal.(1974)ShocksandCMEs‘organize’GCRs• PilesupandDepletions
• Earlyideaabout‘path-clearing’byCMEs
• DevelopingideasaboutForbush Decreases
• Illing andHundhausen (1983)three-partCME
• Shea andSmart(1992)Particlesacceleratedbetweenfastmovinginterplanetary(IP)structures
• SeedparticlesinIPmedium• ModifyearlierideasaboutsourcesofSEPeventsand“Protonflares’
• August72primaryexampleofcombinedForbushDecreaseandEnhancedSEPs
• Gosling(1993)CMEs(ratherthanflares)areprimarydrivingofgeomagneticactivity
ProgressinUnderstandingExtremeShocks&CMEs(2)
http://nevod.mephi.ru
• Gopalswamy (2001)‘cannibal’andinteractingCMEs
• Liuetal.(2014)Path-clearingCMEspermitevenfastersubsequenthomologousCMEs• July2012UltrafastSTEREO-Ashock/CME
• Lugaz etal(2015)ShocksinsideCMEs
ProgressinUnderstandingExtremeShocks&CMEs(3)
Liuetal(2014)Observationsofanextremestormininterplanetaryspacecausedbysuccessivecoronalmassejections,NatureCommunications
• Kozyra etal(2013)FilamentmaterialoriginallybehindCMEmovesthroughCMEtointeractwithshock
• Producesextremeeffectson21Jan2005
• Chatterjee(2018)demonstrateformationofadeltasunspot
• Fromthecollisionoftwoormoreyoungfluxemergingregionsdevelopinginclosevicinity.
• Formationofdensefilamentinoverlyingregion
ProgressinUnderstandingExtremeShocks&CMEs(4)
Kozyra,J.U.,W.B.ManchesterIV,C.P.Escoubet,S.T.Lepri,M.W.Liemohn,W.D.Gonzalez,M.W.Thomsen,andB.T.Tsurutani (2013),Earth’scollisionwithasolarfilamenton21January2005:Overview,J.Geophys.Res.SpacePhysics,118,5967–5978,doi:10.1002/jgra.50567.
• Saiz etal.(2015)&Cidetal.(2105)• highsolarwindpressureandabruptreversalsoftheIMFappearastheinterplanetarytriggerofsharpgeomagneticfieldperturbationsinextremestorms.
• Possiblerootsofimpulsivefield-alignedcurrentpenetrationtomidandlowlatitudes
• ConsistentwithSSCandSIlateon4Aug72&auroraincentralEurope
• Possiblyassociatedwithsolar-drivendetonationofdozens(maybethousands)seaminesonthatdate
ProgressinUnderstandingExtremeShocks&CMEsEffectsatEarth—Carrington-classstorms
Albertson&Thorson, (1974),
Cidetal(2014)
Summary:FromSuntoMudAExtremeEventStruckEarth4Aug72• SEPsdisruptedspacecraft/missions• DestabilizedsomeoftheNorth
AmericanPowerGrid• dB/dt detonatedSeaMinesin
SoutheastAsia
• Rootedinreversepolaritydeltaspot• Eruption
• movedthrough clear-path• Carriedsolarfilamentmatieral• producedGLEandForbush
Decrease• Impulsivemagnetopause
compressionandFACs• Weareonthevergeofunderstanding
theseextremeevents• Modelswillbechallenged
•Knipp,D. J., et al. (2018), On the Little-Known Consequences of the 4 August 1972 Ultra-Fast Coronal Mass Ejecta: Facts, Commentary and Call to Action, Space Weather, 16. https://doi.org/10.1029/2018SW002024