Imaging Convection and Magnetism in the Sun

144 Pages·2016·5.186 MB·English

by  Shravan Hanasoge

SPRINGER BRIEFS IN MATHEMATICS
Shravan Hanasoge
Imaging
Convection and
Magnetism in the
Sun
123
SpringerBriefs in Mathematics
SeriesEditors
NicolaBellomo
MicheleBenzi
PalleE.T.Jorgensen
TatsienLi
RoderickMelnik
OtmarScherzer
BenjaminSteinberg
LotharReichel
YuriTschinkel
G.GeorgeYin
PingZhang
SpringerBriefsinMathematicsshowcasesexpositionsinallareasofmath-
ematics and applied mathematics. Manuscripts presenting new results or a
single new result in a classical field, new field, or an emerging topic, ap-
plications,orbridgesbetweennewresultsandalreadypublishedworks,are
encouraged. The series is intended for mathematicians and applied mathe-
maticians.
Moreinformationaboutthisseriesathttp://www.springer.com/series/10030

Shravan Hanasoge
Imaging Convection
and Magnetism in the Sun
123
ShravanHanasoge
DepartmentofAstronomyandAstrophysics
TataInstituteofFundamentalResearch
Mumbai,India
ISSN2191-8198 ISSN2191-8201 (electronic)
SpringerBriefsinMathematics
ISBN978-3-319-27328-0 ISBN978-3-319-27330-3 (eBook)
DOI10.1007/978-3-319-27330-3
LibraryofCongressControlNumber:2015957966
Mathematics Subject Classification (2010): 35B27, 47A05, 47B25, 15A29, 15A09, 65N12, 65N06,
65N21,35R30,65N22,65N80,35L05,35L10,35L15,35L20,35Q93,85A30,76W05,76R10,78M20,
78M22,86A15,86A22,35Q31,35Q35
SpringerChamHeidelbergNewYorkDordrechtLondon
©TheAuthor2015
Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof
thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation,
broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation
storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology
nowknownorhereafterdeveloped.
Theuseofgeneraldescriptivenames,registerednames,trademarks,servicemarks,etc.inthispublication
doesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevant
protectivelawsandregulationsandthereforefreeforgeneraluse.
Thepublisher,theauthorsandtheeditorsaresafetoassumethattheadviceandinformationinthisbook
arebelievedtobetrueandaccurateatthedateofpublication.Neitherthepublishernortheauthorsor
theeditorsgiveawarranty,expressorimplied,withrespecttothematerialcontainedhereinorforany
errorsoromissionsthatmayhavebeenmade.
Printedonacid-freepaper
SpringerInternationalPublishingAGSwitzerlandispartofSpringerScience+BusinessMedia(www.
springer.com)
Formyparents.

Foreword
HelioseismologyrevolutionizedthestudyoftheSun.Asrecentlyastheearly1970s,
itseemedinconceivablethatscientistscouldstudythesolarinteriorobservationally.
All understanding of the interior structure and dynamics of the Sun was based on
observations of the surface properties of the Sun and other stars and theoretical
modellingofstellarstructureandevolution.
Muchoftherevolutionthathasoccurredintheinterveningtimehasbeenbased
onglobalhelioseismology:thestudyofthesolarinteriorusingtheobservedprop-
ertiesofglobalresonantoscillationsoftheSun.TheobservationaldataareDoppler
velocity measurements and brightness variations at or just above the Sun’s photo-
sphere (its visible surface). The subject leapt forward with new, highly spatially
resolved data from ground-based networks and from space. These highly resolved
measurementsinturnopenedupnewareasofhelioseismology,collectivelyknown
aslocalhelioseismology,thatarebasedontheanalysisofpropertiesofwavesob-
servedonthesolarsurface.Dr.Hanasogehasbeenapioneerinthemodellingand
analysis of such waves and has done much to bridge the gap between two disci-
plines:theseismologyoftheEarthandtheseismologyoftheSun.
In this book, Dr. Hanasoge presents a comprehensive treatment of the forward
and inverse modelling of helioseismology from a fundamental wave theoretic per-
spective. His treatment complements but goes far beyond the other textbooks cur-
rently available that treat helioseismology. Drawing on an extensive literature and
experience in geo-seismology, Dr. Hanasoge demonstrates how these approaches
can be applied to the seismic study of the Sun. This book is a rich resource for
anystudentorresearcherwishingtounderstandordeveloplocalhelioseismictech-
niquesformeasuringtheinternalstructure,dynamicsormagneticfieldsintheSun.
Assuch,Iexpectittobecomewidelyusedinthehelioseismicresearchcommunity.
Someofthematerialishard,tobesure.ButDr.Hanasoge’sclearstyleandexpertise
willopenupthefieldtothediligentstudent.
vii
viii Foreword
Thefieldofhelioseismologyhasmuchstilltoofferforourunderstandingofthe
physicsofthesolarinterior.Researcherswhowishtoengagewiththischallenging
butintriguingfieldwillfindmuchtovalueinthisbook.
Boulder,CO,USA MichaelThompson
March2015
Preface
Our pedestrian Sun is an extraordinary object, exhibiting complex dynamics; we
forgetattimesthatwelivewithastar.Thefirsthistoricalrecordoftheinconstancy
of the Sun is attributed to the Chinese, who, more than two millennia ago, made
sketchesofaspottedSun.FastforwardtotheearlysixteenhundredsGalileo,among
othercontemporaries,begantoobserveanddescribethesespotswithhisthen-newly
inventedtelescope.Hewasthefirsttodemonstratetheywereonthesurfaceofthe
Sun,implyingthattheywereindeedsolarinorigin.Fourhundredyearson,contem-
porarysolarphysicsisdrivenbyexpensiveinternationalspacemissionsandbillion
dollarspacetelescopesobservetheSunathighresolution,beamingdownaterabyte
ofdataeveryday.Itisstrikingtoviewtheprogressionofourunderstandingofthe
Sun,fromancientsketchesofsunspotstodetailedmodelsofstructureandinternal
rotationandelaboratetheoriesofglobalmagneticfieldgeneration.Therefinement
in our appreciation of the structure and dynamics of the Sun from what we knew
even in the late nineteen sixties is remarkable. Not only has the Sun shed insight
onstellarphysics,i.e.thestudyofthestructure,evolutionanddynamicsofstars,it
continuestobearelevantobjectofstudytoday.
The Sun’s magnetic field directly affects Earth climate and space weather. The
internalmechanismthatgovernstheSun’slarge-scalefieldreversalsisasubjectof
greatinteresttodynamotheoristsandastrophysicists.Thepropertiesofconvection
in the highly stratified environment of the solar convection zone provide insights
in a parameter regime inaccessible to computation and laboratory experiment and
arethereforeofrelevancetofluidmechanicians.Solarandstellarphysicsarevery
importantbranchesofastronomyandastrophysics,whosestudyisenabledbysub-
stantialfinancialsupportfrominternationalspaceagencies.Therehavebeensome
ten satellite missions in the fields of solar and stellar physics and the installation
ofanumberofground-basedinstrumentsoverthepasttwodecades,representinga
substantialinvestmentbythescientificcommunity.Asaconsequence,high-quality
observationsoftheSunandstarsarenowabundantlyavailableandsotheburning
questionsnowalmostentirelyconcernaccurateinterpretation.Itisinthisbackdrop
thatthismonographfindsitsrelevance.
ix