Hostname: page-component-77c89778f8-swr86 Total loading time: 0 Render date: 2024-07-17T18:18:53.507Z Has data issue: false hasContentIssue false

Generation and Annihilation of Magnetic Helicity in Active Regions

Published online by Cambridge University Press:  30 March 2016

K. Kusano*
Affiliation:
Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Generation and annihilation processes of magnetic helicity in solar coronal active regions are investigated based on the observations and the simulations. We first examined the reliability of the numerical techniques, which enable to measure the magnetic helicity flux through the photosphere based on the magnetogram data. Secondly, in terms of the new technique, we found that magnetic helicities of the both signs are simultaneously injected into active regions. Motivated by this result, finally, we investigated the nonlinear process of the magnetic helicity annihilation, using the three-dimensional numerical simulations. The simulations clearly indicated that the helicity reversal can cause the eruption of large-scale plasmoid through the nonlinear process of the resistive instability growing on the helicity inversion layer. From these studies, we point out that the annihilation of magnetic helicity is a key process for the onset mechanism of solar flares.

Type
I. Joint Discussions
Copyright
Copyright © Astronomical Society of Pacific 2005

References

Berger, M.A., Field, G.B. 1984, J. Fluid Mech., 147, 133 CrossRefGoogle Scholar
Démoulin, P. & Berger, M.A. 2003, Solar Phys., 215, 203 CrossRefGoogle Scholar
Kusano, K., Maeshiro, T., Yokoyama, T., & Sakukrai, T. 2002, ApJ, 577, 501 CrossRefGoogle Scholar
Kusano, K., Maeshiro, T., Yokoyama, T., & Sakukrai, T. 2003, Advances in Space Research, 32, 1917 CrossRefGoogle Scholar