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dc.contributor.authorTziotziou, K.
dc.contributor.authorMoraitis, K.
dc.contributor.authorGeorgoulis, M.K.
dc.contributor.authorArchontis, V.
dc.identifier.citationTziotziou , K , Moraitis , K , Georgoulis , M K & Archontis , V 2014 , ' Validation of the magnetic energy vs. helicity scaling in solar magnetic structures ' , Astronomy & Astrophysics , vol. 570 , L1 .
dc.identifier.otherPURE: 158991264
dc.identifier.otherPURE UUID: 1e60b3a6-e685-429b-abba-9f0d7efb0867
dc.identifier.otherScopus: 84907906495
dc.identifier.otherWOS: 000344158500147
dc.identifier.otherORCID: /0000-0002-6926-8676/work/73700842
dc.descriptionV.A. acknowledges support by the Royal Society. This work was supported from the EU’s Seventh Framework Program under grant agreement n° PIRG07-GA-2010-268245. It has been also cofinanced by the European Union (European Social Fund – ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) – Research Funding Program: Thales.en
dc.description.abstractAims. We assess the validity of the free magnetic energy - relative magnetic helicity diagram for solar magnetic structures.Methods. We used two different methods of calculating the free magnetic energy and the relative magnetic helicity budgets: a classical, volume-calculation nonlinear force-free (NLFF) method applied to finite coronal magnetic structures and a surface-calculation NLFF derivation that relies on a single photospheric or chromospheric vector magnetogram. Both methods were applied to two different data sets, namely synthetic active-region cases obtained by three-dimensional magneto-hydrodynamic (MHD) simulations and observed active-region cases, which include both eruptive and noneruptive magnetic structures.Results. The derived energy-helicity diagram shows a consistent monotonic scaling between relative helicity and free energy with a scaling index 0.84 +/- 0.05 for both data sets and calculation methods. It also confirms the segregation between noneruptive and eruptive active regions and the existence of thresholds in both free energy and relative helicity for active regions to enter eruptive territory.Conclusions. We consider the previously reported energy-helicity diagram of solar magnetic structures as adequately validated and envision a significant role of the uncovered scaling in future studies of solar magnetism.
dc.relation.ispartofAstronomy & Astrophysicsen
dc.rightsReproduced with permission from Astronomy & Astrophysics, © ESOen
dc.subjectSun: chromosphereen
dc.subjectSun: magnetic fieldsen
dc.subjectSun: photosphereen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.titleValidation of the magnetic energy vs. helicity scaling in solar magnetic structuresen
dc.typeJournal itemen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. Applied Mathematicsen
dc.description.statusPeer revieweden

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