The Magnetic Helicity Injected by Shearing Motions

dc.creatorDémoulin, Pascal
dc.creatorMandrini, Cristina Hemilse
dc.creatorvan Driel Gesztelyi, Lidia
dc.creatorLopez Fuentes, Marcelo Claudio
dc.creatorAulanier, G.
dc.date2002-05
dc.identifierhttp://hdl.handle.net/11336/22459
dc.identifierDémoulin, Pascal; Mandrini, Cristina Hemilse; van Driel Gesztelyi, Lidia; Lopez Fuentes, Marcelo Claudio; Aulanier, G.; The Magnetic Helicity Injected by Shearing Motions; Springer; Solar Physics; 207; 1; 5-2002; 87-110
dc.identifier0038-0938
dc.identifierCONICET Digital
dc.identifierCONICET
dc.descriptionPhotospheric shearing motions are one of the possible ways to inject magnetic helicity into the corona. We explore their efficiency as a function of their particular properties and those of the magnetic field configuration. Based on the work of M. A. Berger, we separate the helicity injection into two terms: twist and writhe. For shearing motions concentrated between the centers of two magnetic polarities the helicity injected by twist and writhe add up, while for spatially more extended shearing motions, such as differential rotation, twist and writhe helicity have opposite signs and partially cancel. This implies that the amount of injected helicity can change in sign with time even if the shear velocity is time independent. We confirm the amount of helicity injected by differential rotation in a bipole in the two particular cases studied by DeVore (2000), and further explore the parameter space on which this injection depends. For a given latitude, tilt and magnetic flux, the generation of helicity is slightly more efficient in young active regions than in decayed ones (up to a factor 2). The helicity injection is mostly affected by the tilt of the AR with respect to the solar equator. The total helicity injected by shearing motions, with both spatial and temporal coherence, is at most equivalent to that of a twisted flux tube having the same magnetic flux and a number of turns of 0.3. In the solar case, where the motions have not such global coherence, the injection of helicity is expected to be much smaller, while for differential rotation this maximum value reduces to 0.2 turns. We conclude that shearing motions are a relatively inefficient way to bring magnetic helicity into the corona (compared to the helicity carried by a significantly twisted flux tube).
dc.descriptionFil: Démoulin, Pascal. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia
dc.descriptionFil: Mandrini, Cristina Hemilse. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
dc.descriptionFil: van Driel Gesztelyi, Lidia. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia
dc.descriptionFil: Lopez Fuentes, Marcelo Claudio. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
dc.descriptionFil: Aulanier, G.. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia
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dc.formatapplication/pdf
dc.formatapplication/pdf
dc.languageeng
dc.publisherSpringer
dc.relationinfo:eu-repo/semantics/altIdentifier/url/https://link.springer.com/article/10.1023/A:1015531804337
dc.relationinfo:eu-repo/semantics/altIdentifier/doi/10.1023/A:1015531804337
dc.rightsinfo:eu-repo/semantics/openAccess
dc.rightshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subjectSolar Magnetic Fields
dc.subjectPhotospheric Motions
dc.subjectMagnetic Helicity
dc.subjecthttps://purl.org/becyt/ford/1.3
dc.subjecthttps://purl.org/becyt/ford/1
dc.titleThe Magnetic Helicity Injected by Shearing Motions
dc.typeinfo:eu-repo/semantics/article
dc.typeinfo:ar-repo/semantics/artículo
dc.typeinfo:eu-repo/semantics/publishedVersion


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