Microphysics of Cosmic Plasmas, Space Sciences Series of ISSI</SeriesTitle></SeriesInfo><Book Language="En"><BookInfo BookProductType="Monograph" ContainsESM="No" Language="En" MediaType="eBook" NumberingStyle="ContentOnly" OutputMedium="All" TocLevels="0"><BookID>978-1-4899-7413-6</BookID><BookTitle>Microphysics of Cosmic Plasmas</BookTitle><BookVolumeNumber>47</BookVolumeNumber><BookSequenceNumber>48</BookSequenceNumber><BookDOI>10.1007/978-1-4899-7413-6</BookDOI><BookTitleID>321534</BookTitleID><BookPrintISBN>978-1-4899-7412-9</BookPrintISBN><BookElectronicISBN>978-1-4899-7413-6</BookElectronicISBN><BookChapterCount>22</BookChapterCount><BookCopyright><CopyrightHolderName>Springer Science+Business Media New York</CopyrightHolderName><CopyrightYear>2014</CopyrightYear></BookCopyright><BookSubjectGroup><BookSubject Code="SCP" Type="Primary">Physics</BookSubject><BookSubject Code="SCP22030" Priority="1" Type="Secondary">Extraterrestrial Physics, Space Sciences</BookSubject><BookSubject Code="SCP24040" Priority="2" Type="Secondary">Plasma Physics</BookSubject><SubjectCollection Code="SUCO11651">Physics and Astronomy</SubjectCollection></BookSubjectGroup><BookContext><SeriesID>6592</SeriesID></BookContext></BookInfo><BookHeader><EditorGroup><Editor AffiliationIDS="Aff1"><EditorName DisplayOrder="Western"><GivenName>André</GivenName><FamilyName>Balogh</FamilyName></EditorName></Editor><Editor AffiliationIDS="Aff2"><EditorName DisplayOrder="Western"><GivenName>Andrei</GivenName><FamilyName>Bykov</FamilyName></EditorName></Editor><Editor AffiliationIDS="Aff1"><EditorName DisplayOrder="Western"><GivenName>Peter</GivenName><FamilyName>Cargill</FamilyName></EditorName></Editor><Editor AffiliationIDS="Aff3"><EditorName DisplayOrder="Western"><GivenName>Richard</GivenName><FamilyName>Dendy</FamilyName></EditorName></Editor><Editor AffiliationIDS="Aff4"><EditorName DisplayOrder="Western"><GivenName>Thierry</GivenName><FamilyName>Dudok de Wit</FamilyName></EditorName></Editor><Editor AffiliationIDS="Aff5"><EditorName DisplayOrder="Western"><GivenName>John</GivenName><FamilyName>Raymond</FamilyName></EditorName></Editor><Affiliation ID="Aff1"><OrgName>Imperial College London</OrgName><OrgAddress><City>London</City><Country>UK</Country></OrgAddress></Affiliation><Affiliation ID="Aff2"><OrgName>Russian Academy of Sciences</OrgName><OrgAddress><City>St. Petersburg</City><Country>Russia</Country></OrgAddress></Affiliation><Affiliation ID="Aff3"><OrgName>Euratom/UKAEA Fusion Association</OrgName><OrgAddress><City>Abingdon</City><Country>UK</Country></OrgAddress></Affiliation><Affiliation ID="Aff4"><OrgName>LPC2E/CNRS-University of Orleans</OrgName><OrgAddress><City>Orleans Cedex 2</City><Country>France</Country></OrgAddress></Affiliation><Affiliation ID="Aff5"><OrgName>Harvard-Smithsonian Center for Astrophysics</OrgName><OrgAddress><City>Cambridge</City><State>MA</State><Country>USA</Country></OrgAddress></Affiliation></EditorGroup></BookHeader><Chapter ID="Chap4" Language="En"><ChapterInfo ChapterType="OriginalPaper" ContainsESM="No" Language="En" NumberingStyle="ContentOnly" TocLevels="0"><ChapterID>4</ChapterID><ChapterDOI>10.1007/978-1-4899-7413-6_4</ChapterDOI><ChapterSequenceNumber>4</ChapterSequenceNumber><ChapterTitle Language="En">Solar Surface and Atmospheric Dynamics</ChapterTitle><ChapterSubTitle Language="En">The Photosphere</ChapterSubTitle><ChapterFirstPage>65</ChapterFirstPage><ChapterLastPage>86</ChapterLastPage><ChapterCopyright><CopyrightHolderName>Springer Science+Business Media Dordrecht</CopyrightHolderName><CopyrightYear>2013</CopyrightYear></ChapterCopyright><ChapterGrants Type="Regular"><MetadataGrant Grant="OpenAccess"/><AbstractGrant Grant="OpenAccess"/><BodyPDFGrant Grant="Restricted"/><BodyHTMLGrant Grant="Restricted"/><BibliographyGrant Grant="Restricted"/><ESMGrant Grant="Restricted"/></ChapterGrants><ChapterContext><SeriesID>6592</SeriesID><BookID>978-1-4899-7413-6</BookID><BookTitle>Microphysics of Cosmic Plasmas</BookTitle></ChapterContext></ChapterInfo><ChapterHeader><AuthorGroup><Author AffiliationIDS="Aff6" CorrespondingAffiliationID="Aff6"><AuthorName DisplayOrder="Western"><GivenName>V.</GivenName><FamilyName>Martínez Pillet</FamilyName></AuthorName><Contact><Phone>+34-922-605237</Phone><Fax>+34-922-605210</Fax> vmp [at] iac.es (vmp[at]iac[dot]es) </Contact></Author><Affiliation ID="Aff6"><OrgName>Instituto de Astrofísica de Canarias</OrgName><OrgAddress><Postcode>38200</Postcode><City>La Laguna, Tenerife</City><Country>Spain</Country></OrgAddress></Affiliation></AuthorGroup><Abstract ID="Abs1" Language="En" OutputMedium="All"><Heading>Abstract</Heading><Para>Various aspects of the magnetism of the quiet sun are reviewed. The suggestion that a small scale dynamo acting at granular scales generates what we call the quiet sun fields is studied in some detail. Although dynamo action has been proved numerically, it is argued that current simulations are still far from achieving the complexity that might be present on the Sun. We based this statement not so much on the low magnetic Reynolds numbers used in the simulations but, above all, in the smallness of the kinetic Reynolds numbers employed by them. It is argued that the low magnetic Prandtl number at the solar surface may pose unexpected problems for the identification of the observed internetwork fields with dynamo action at granular scales. Some form of turbulent dynamo at bigger (and deeper) scales is favored. The comparison between the internetwork fields observed by Hinode and the magnetism inferred from Hanle measurements are converging towards a similar description. They are both described as randomly oriented, largely transverse fields in the several hecto-Gauss range. These similarities are ever making more natural to assume that they are the same. However, and because of the large voids of magnetic flux observed in the spatial distribution of the internetwork fields, it is argued that they are not likely to be generated by dynamo action in the intergranular lanes. It is concluded that if a dynamo is acting at granular scales, the end product might have not been observed yet at current spatial resolutions and sensitivities with the Zeeman effect. Thus an effort to increase these resolutions and polarimetric sensitivities must be made. New ground- and space-based telescopes are needed. The opportunity offered by the Solar Orbiter mission to observe the Quiet Sun dynamics at the poles is seen as one of the most important tests for confirming the existence, or otherwise, of a granularly driven surface dynamo.
Bibcode
Martínez Pillet, V.
Bibliographical reference
Advertised on:
2014
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Description
Various aspects of the magnetism of the quiet sun are reviewed. The
suggestion that a small scale dynamo acting at granular scales generates
what we call the quiet sun fields is studied in some detail. Although
dynamo action has been proved numerically, it is argued that current
simulations are still far from achieving the complexity that might be
present on the Sun. We based this statement not so much on the low
magnetic Reynolds numbers used in the simulations but, above all, in the
smallness of the kinetic Reynolds numbers employed by them. It is argued
that the low magnetic Prandtl number at the solar surface may pose
unexpected problems for the identification of the observed internetwork
fields with dynamo action at granular scales. Some form of turbulent
dynamo at bigger (and deeper) scales is favored. The comparison between
the internetwork fields observed by Hinode and the magnetism inferred
from Hanle measurements are converging towards a similar description.
They are both described as randomly oriented, largely transverse fields
in the several hecto-Gauss range. These similarities are ever making
more natural to assume that they are the same. However, and because of
the large voids of magnetic flux observed in the spatial distribution of
the internetwork fields, it is argued that they are not likely to be
generated by dynamo action in the intergranular lanes. It is concluded
that if a dynamo is acting at granular scales, the end product might
have not been observed yet at current spatial resolutions and
sensitivities with the Zeeman effect. Thus an effort to increase these
resolutions and polarimetric sensitivities must be made. New ground- and
space-based telescopes are needed. The opportunity offered by the Solar
Orbiter mission to observe the Quiet Sun dynamics at the poles is seen
as one of the most important tests for confirming the existence, or
otherwise, of a granularly driven surface dynamo.