Plasma Sources of Solar System Magnetospheres

296 Pages·2016·24.968 MB·English

by  Andrew F. Nagy, Michel Blanc, Charles R. Chappell, Norbert Krupp (eds.)

SPACE SCIENCES SERIES OF ISSI
Plasma Sources
of Solar System
Magnetospheres
Andrew F. Nagy · Michel Blanc
Editors
Charles R. Chappell · Norbert Krupp
123
Space Sciences Series of ISSI
Volume 52
Forfurthervolumes:
www.springer.com/series/6592
Andrew F. Nagy (cid:2) Michel Blanc (cid:2)
Charles R. Chappell (cid:2) Norbert Krupp
Editors
Plasma Sources of Solar
System Magnetospheres
Previously published in Space Science Reviews Volume 192,
Issues 1–4, 2015
Editors
AndrewF.Nagy CharlesR.Chappell
UniversityofMichigan VanderbiltUniversity
AnnArbor,MI,USA Nashville,TN,USA
MichelBlanc
InstitutdeRechercheenAstrophysique NorbertKrupp
etPlanétologie Max-PlanckInstitutfürSonnensystem
Toulouse,France Göttingen,Germany
ISSN1385-7525 SpaceSciencesSeriesofISSI
ISBN978-1-4939-3543-7 ISBN978-1-4939-3544-4(eBook)
DOI10.1007/978-1-4939-3544-4
LibraryofCongressControlNumber:2016931193
SpringerNewYorkHeidelbergDordrechtLondon
©SpringerScience+BusinessMediaNewYork2016
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CoverImage:EnceladusasamajorsourceforSaturn’smagnetosphere.Credit:MargaretKivelsonetal.,Does
EnceladusgovernmagnetosphericdynamicsatSaturn?Science311,1391(2006)
Printedonacid-freepaper
SpringerispartofSpringerScience+BusinessMedia(www.springer.com)
Contents
Foreword
(cid:3)
M.Blanc A.F.Nagy 1
TheRoleoftheIonosphereinProvidingPlasmatotheTerrestrial
Magnetosphere—AnHistoricalOverview
C.R.Chappell 5
AReviewofGeneralPhysicalandChemicalProcessesRelatedtoPlasmaSources
andLossesforSolarSystemMagnetospheres
(cid:3) (cid:3) (cid:3) (cid:3) (cid:3) (cid:3) (cid:3)
K.Seki A.Nagy C.M.Jackman F.Crary D.Fontaine P.Zarka P.Wurz
(cid:3) (cid:3) (cid:3) (cid:3) (cid:3) (cid:3) (cid:3)
A.Milillo J.A.Slavin D.C.Delcourt M.Wiltberger R.Ilie X.Jia S.A.Ledvina
(cid:3)
M.W.Liemohn R.W.Schunk 27
PlasmaSourcesinPlanetaryMagnetospheres:Mercury
(cid:3) (cid:3) (cid:3) (cid:3) (cid:3) (cid:3)
J.M.Raines G.A.DiBraccio T.A.Cassidy D.C.Delcourt M.Fujimoto X.Jia
(cid:3) (cid:3) (cid:3) (cid:3)
V.Mangano A.Milillo M.Sarantos J.A.Slavin P.Wurz 91
TheEarth:PlasmaSources,Losses,andTransportProcesses
(cid:3) (cid:3) (cid:3) (cid:3) (cid:3) (cid:3)
D.T.Welling M.André I.Dandouras D.Delcourt A.Fazakerley D.Fontaine
(cid:3) (cid:3) (cid:3) (cid:3) (cid:3) (cid:3) (cid:3)
J.Foster R.Ilie L.Kistler J.H.Lee M.W.Liemohn J.A.Slavin C.-P.Wang
(cid:3)
M.Wiltberger A.Yau 145
Jupiter’sMagnetosphere:PlasmaSourcesandTransport
(cid:3) (cid:3) (cid:3) (cid:3) (cid:3) (cid:3) (cid:3)
S.J.Bolton F.Bagenal M.Blanc T.Cassidy E.Chané C.Jackman X.Jia
(cid:3) (cid:3) (cid:3) (cid:3) (cid:3)
A.Kotova N.Krupp A.Milillo C.Plainaki H.T.Smith H.Waite 209
SaturnPlasmaSourcesandAssociatedTransportProcesses
(cid:3) (cid:3) (cid:3) (cid:3) (cid:3) (cid:3)
M.Blanc D.J.Andrews A.J.Coates D.C.Hamilton C.M.Jackman X.Jia
(cid:3) (cid:3) (cid:3)
A.Kotova M.Morooka H.T.Smith J.H.Westlake 237
ComparisonofPlasmaSourcesinSolarSystemMagnetospheres
N.Krupp 285
DOI10.1007/978-1-4939-3544-4_1
ReprintedfromSpaceScienceReviewsJournal,DOI10.1007/s11214-015-0205-4
Foreword
MichelBlanc1·AndrewF.Nagy2
Publishedonline:12October2015
©SpringerScience+BusinessMediaDordrecht2015
InSeptember1999,ISSIpublishedavolumeentitled“MagnetosphericPlasmaSourcesand
Losses”, edited by Bengt Hultqvist and collaborators. This volume, which was the result
ofatwo-yearpreparationandstudyprocesswithinthe“ISSIStudyProjectonSourceand
Loss Processes”, aimed at giving a comprehensive view of what we knew at that time of
Earth’s magnetospheric plasma sources and losses. To reach this ambitious objective, the
teamhaddividedtheEarth’splasmaenvironmentintospecificregions,andineachregion
the budget of sources and losses of plasma and energetic particles was established, based
onthenumberofspacecraftinvestigationsavailable.Forthesources,essentiallytwowere
considered,theionosphereandthesolarwind,andthecirculationpathsbymeansofwhich
thesetwosourcesfeedeachregionweretraced.
Approximately one and a half decade later, it seemed relevant to revisit this issue of
plasma sources. Indeed, since the late 1990’s comprehensive results from several orbital
missionstotheintrinsicplanetarymagnetospheresofthesolarsystemhavebecomeavail-
able: Galileo at Jupiter, Cassini at Saturn, and more recently Messenger around Mercury.
This is the reason why, following a suggestion by Andrew F. Nagy, the directors of ISSI
decidedtotakeadvantageofthishostofspacemissionstotheplanetstostudythebudgetof
plasmasourcesnotonlyfortheEarth,butthistimeforallintrinsicmagnetospheresinour
solarsystem.Tothisend,anISSIworkshopgatheringover40ofthebestspecialistswork-
ingonthesetopicswasheldinBernfromSeptember23rdto27th,2013,withthetaskof
performingastudyofmagnetosphericplasmasourcesinthesolarsystem,andofpreparing
thewritingofacomprehensivebookonthesubject.
Inthisperspective,theworkshopparticipantshadtofaceandmanagethebroaddiversity
ofthesubject:first,thediversityoftheobjectstobeconsidered,fromMercurytoNeptune,
but also, and above all, the diversity in the sources of the plasmas themselves. While for
Earthin1999wehad,andstillhaveafewyearslater,toconsideronlytwoplasmasources,
B M.Blanc
[email protected]
1 IRAP/OMP,Toulouse,France
2 UniversityofMichigan,AnnArbor,MI,USA
1 Reprintedfromthejournal
M.Blanc,A.F.Nagy
ionosphereandsolarwind,inourvisittoallsolarsystemmagnetosphereswehadtoinclude
newandcomplexplasmasources:satellitesandrings(atthegiantplanets),ortheplanetary
surfaceitself(forMercury),someofwhichactuallyhappentobethedominantsources.
Thisbookreportsonourfindingsalongthisfulltourofthesolarsystemperformedby
theworkshopparticipants.Itstartswithtwointroductorychapterswhichsetthestageand
providethebasictoolsforourvisittosolarsystemmagnetospheres.
Inthefirstintroductorychapter,RickChappellprovidesahistoricalperspectiveonthe
studyofplasmasourcesatEarth,showinginparticularhowourunderstandingoftheiono-
sphericsourceevolvedandhowitbecameunderstoodtobemoreandmoreimportantwith
time, and has to be considered now at least on equal footings with the solar wind source.
Hischapter teaches ushowtheavailability ofnewspacedataandprogressinsimulations
transformedourviewofplasmasources:alessoncertainlytobekeptinmindforallother
magnetospheres.
Inthesecondchapter,KanakoSekiandherco-authorsprovideanoverviewofthemain
physical processes that are at work in the expression of sources, transport and losses in
the different regions of a magnetosphere and at various energies. The chapter also nicely
summarizes the main equations used for the description of these processes, and the main
typesofmodelingtoolsthathavebeendevelopedtosimulatethem.Inthatwayitprovidesus
withthe“toolbox”thatweneedtostartourexplorationofthesolarsystemandunderstand
thedataandmodels.
ThisexplorationisperformedfromclosesttotheSunoutwards,andthereforestartswith
theplanetMercury.JimRainesandco-authorsusesomeofthelatestdatafromtheMessen-
gerorbitertovisittheplasmasourcesandthedynamicsofthistinymagnetosphere,where
theinfluenceofthesolarwindisdominant,butalsowherethedirectinteractionofmagne-
tosphericparticlesandfieldswiththeexosphereandsurfaceoftheplanetplaysarolelike
nowhereinthesolarsystem,exceptmaybeatJupiter’ssatelliteGanymede.Theveryshort
timescaleswithinwhichthemagnetosphericconfigurationandtheplasmadomainsofthis
magnetospherearereconfiguredarealsouniqueinthesolarsystem.
ThenextobjectinourexplorationisplanetEarth:DanWellingetal.reviewtheprogress
madeinourunderstandingofEarth’splasmasourcesandsubsequenttransport,acceleration
and loss processes since the comprehensive ISSI book of 1999. They consider both the
observational and the modelling advances achieved since that time, and establish a new
referenceforthedescriptionofEarth’sbasicplasmaprocesses.
The book then moves on to the exploration of giant planets, starting with Jupiter. As
Bolton et al. write in their introduction to this chapter, the Jupiter system is “a world of
superlatives”: biggest planet in the solar system, strongest magnetic field, largest magne-
tosphere,andwiththemostintenseplasmasources.JupiterisdominatedbytheIoplasma
source, which under the effect of the planet’s centrifugal action generates a large plasma
disc.Giventhis,Jupiterisnotjustthelargestmagnetosphere,itisalsotheclosestobjectto
a proto-planetary disk we have at hand in our solar system, and to some extent it bridges
thegapbetweenplanetarysciencesandastrophysics.Thechaptersummarizesthedifferent
plasmasourcesassociatedwiththisfascinatingobject,andthewaytheyaretransportedand
lostfromtheirregionsoforigintotheouteredgesofthemagnetosphere.
Saturn,Jupiter’ssisterplanetandoursolarsystem’ssecondgasgiantbyitssize,isde-
scribedinthenextchapterbyBlancetal.JustastheSaturnsystemisdiverseintermsof
theobjectsitincludes,itsplasmasourcesdisplayabroaddiversity,whichhasbeenexplored
in considerable detail by Cassini since it went into orbit around Saturn in July 2004. The
ringsandsatellitesallcontributetoitsplasmasources,butthespaceexplorationofSaturn
revealed,quiteunexpectedly,thatthedominantsourceisthetinysatelliteEnceladus.Even
Reprintedfromthejournal 2
Foreword
Titan, the largest moon in the system and the only one with a thick atmosphere, plays a
minorrolecomparedtoit.So,likeJupiter,Saturnisdominatedbyasinglesource.
UranusandNeptune,ourtwoicegiantsattheoutskirtsofthesolarsystem,aredescribed
byNorbertKruppinthefinalchapterofthebook.Thesetwoplanetsarebyfartheleastwell
known,sincewhatweknowofthemonlycomesfromthefly-bysofVoyager2in1986and
1989.TheVoyagerdatasuggestthatplasmaatUranusisproducedmainlybyitshydrogen
corona with a likely complement from its ionosphere, whereas at Neptune the dominant
sourceseemstobeassociatedwithitssatelliteTriton.
Intheremainderofhischapter,NorbertKruppoffersafinalreviewofalltheplanetary
plasmasourcesexploredbythebook,emphasizingthemainsimilaritiesanddifferencesbe-
tweenthem.Overall,oneseesthatmoreorlessallthesamecategoriesofsourcesareacting
at the different planets, but the dominant ones vary strongly from one planet to another.
We hope this book will provide the reader with agood opportunity to visit this variety of
sources,andtocontemplatethediversityoftheirexpressions.
Before closing this foreword, we would like to thank the Directors and Science Com-
mitteeofISSIfortheirsupporttothisproject,andtoexpressourwarmestappreciationto
thewonderfulstaffofISSI,ISSI’sscienceprogrammemanagerMaurizioFalanga,Jennifer
Fankhauser,AndreaFischer,SalibaF.Saliba,IrmelaSchweizer,SilviaWenger,andalltheir
colleagues,whosekindnessanddedicationmakeISSIsuchaconvivialandeffectiveplace
tointeract,exchangeideasandwork.Thisbookwouldnothavebeenpossiblewithoutallof
them.
3 Reprintedfromthejournal
DOI10.1007/978-1-4939-3544-4_2
ReprintedfromSpaceScienceReviewsJournal,DOI10.1007/s11214-015-0168-5
The Role of the Ionosphere in Providing Plasma
to the Terrestrial Magnetosphere—An Historical
Overview
CharlesR.Chappell1
Received:10March2015/Accepted:25May2015/Publishedonline:10July2015
©SpringerScience+BusinessMediaDordrecht2015
Abstract Through the more than half century of space exploration, the perception and
recognition of the fundamental role of the ionospheric plasma in populating the Earth’s
magnetospherehasevolveddramatically.Abriefhistoryofthisevolutioninthinkingispre-
sented.Boththeoryandmeasurementshaveunveiledasurprisingnewunderstandingofthis
importantionosphere-magnetospheremasscouplingprocess.Thehighlightsofthemystery
surroundingthedifficultyinmeasuringthislargelyinvisiblelowenergyplasmaarealsodis-
cussed.Thismysteryhasbeensolvedthroughthedevelopmentofinstrumentationcapable
ofmeasuringtheselowenergypositively-chargedoutflowingionsinthepresenceofposi-
tivespacecraftpotentials.Thishasledtoasignificantnewunderstandingoftheionospheric
plasmaasasignificantdriverofmagnetosphericplasmacontentanddynamics.
1 Introduction
TheearlyinstrumentationusedonsatellitesthatprobedtheEarth’sspaceenvironmentwas
abletomeasurethefluxesofthelowdensity,highenergyparticlesfoundinthemagneto-
sphere or the high density, very low energy particles typical of the ionosphere. Measure-
mentsofthehighenergyradiationbeltsoriginallyweremadewithGeigercounters,while
the lowenergy plasma of theionosphere wasmeasured withretarding potential analyzers
and Langmuir probes. As miniaturized channel electron multipliers were developed, the
measurement of the full energy range of particles from a few electron volts up to ten’s of
keVbecamepossible.
Asthesenewinstrumentswereflownonsatellitesintothemagnetosphereandsolarwind,
itwasrecognizedthattherewasasimilarityinenergybetweenthesolarwindparticlesand
particlesfoundintheEarth’splasmasheetandaurora.Earlyinstrumentationdidnothavethe
abilitytodetermineioncompositionatthismediumenergyrange,anditwasassumedthat
theplasmasinthesolarwindandthemagnetospherewerebothdominatedbyprotonsand
electrons.HencetheconceptualpictureshowninFig.1wasdeveloped.Inthisunderstanding
B C.R.Chappell
[email protected]
1 VanderbiltUniversity,Nashville,TN,USA
5 Reprintedfromthejournal
C.R.Chappell
Fig.1 Aschematicimage
representingtheearly
understandingoftheprimaryrole
ofthesolarwindinpopulating
theEarth’smagnetospherewith
plasma
ofourspacephysics“childhood”thesolarwindwasseenasthesolesourceofplasmafor
themagnetospherewithsolarwindparticlesgainingaccessintothemagnetospherethrough
thepolarcusponthedaysideandthroughtheflanksofthemagnetotailintotheplasmasheet
on the nightside. These keV ions and electrons were thought to be channeled through the
magneticfielddownintotheauroralzonewheretheycollidedwiththeatomsandmolecules
oftheupperatmospheretocreatetheauroralemissions.TheVanAllenradiationbeltswhich
were the first major discovery of a magnetospheric plasma population are shown in this
figureasatoroidalshapedregionsurroundingtheEarthintheinnermagnetosphere.
Inthisearlyviewofthesolarwind/magnetospheresystem,thelowenergyplasmawas
thought to be confined to the low altitudes of the ionosphere with an extension upward
only in the plasmasphere, a roughly donut-shaped region with an outer average boundary
of about L=4, extending outward to L=6 in the dusk sector. The plasmasphere was
seen to vary with magnetic activity moving inward during disturbed times and growing
largerduringmagneticallyquiettimes(Gringauz1963;Carpenter1963).Earlytheoretical
workbyNishida(1966)andBrice(1967)suggestedwaysinwhichtheconvectionelectric
field in the magnetosphere, combined with the corotation of plasma with the Earth could
begin to explain the presence and shape of the plasmasphere. Later measurements from
theOrbitingGeophysicalObservatoryseriesofspacecraftverifiedtheearlierwhistlerand
satellitemeasurementsandenhancedtheunderstandingofplasmaspheredynamics(Taylor
etal.1965;Brintonetal.1970;Grebowsky1970;Chappell1972).
Although the plasmasphere represented a region of magnetospheric plasma, it was
thought tobeonlyan upwardextension of theionosphereand tobeoftoolowan energy
to contribute to the dynamic magnetospheric processes that created magnetic storms, the
auroraandtheradiationbelts.Hence,discussionsoftheplasmasphereinthoseyearswere
usuallyplacedinionosphericsessionsatthenationalandinternationalmeetingsandnotin
themagnetosphericsessions.
Thiswasthespacephysicscommunityperceptionofthesolarwind-magnetospheresys-
temthroughthedecadeofthe1960s.Thelocationsofthemagnetosphericregionsofmore
energeticparticles,theirenergiesandunknowncompositionshowedanexcellentfittothe
ideathatthesolarwindprovidedboththeenergyandtheparticlesfordrivingthedynamic
processesthatwereobservedinthemagnetospherebybothspace-borneandground-based
measurements.Thisiswhatgraduatestudentsofthattimeweretaughtandtheseideashave
notgoneawayeasily.
Reprintedfromthejournal 6