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Three-dimensional magnetohydrodynamics of the emerging magnetic flux in the solar atmosphereThe nonlinear evolution of an emerging magnetic flux tube or sheet in the solar atmosphere is studied through 3D MHD simulations. In the initial state, a horizontal magnetic flux sheet or tube is assumed to be embedded at the bottom of MHD two isothermal gas layers, which approximate the solar photosphere/chromosphere and the corona. The magnetic flux sheet or tube is unstable against the undular mode of the magnetic buoyancy instability. The magnetic loop rises due to the linear and then later nonlinear instabilities caused by the buoyancy enhanced by precipitating the gas along magnetic field lines. We find by 3D simulation that during the ascendance of loops the bundle of flux tubes or even the flux sheet develops into dense gas filaments pinched between magnetic loops. The interchange modes help produce a fine fiber flux structure perpendicular to the magnetic field direction in the linear stage, while the undular modes determine the overall buoyant loop structure. The expansion of such a bundle of magnetic loops follows the self-similar behavior observed in 2D cases studied earlier. Our study finds the threshold flux for arch filament system (AFS) formation to be about 0.3 x 10 exp 20 Mx.
Document ID
19930071260
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Matsumoto, R.
(Texas Univ. Austin; Chiba Univ., Japan)
Tajima, T.
(Texas Univ. Austin, United States)
Shibata, K.
(National Astronomical Observatory Mitaka, Japan)
Kaisig, M.
(Wuerzburg Univ. Germany)
Date Acquired
August 16, 2013
Publication Date
September 1, 1993
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 414
Issue: 1
ISSN: 0004-637X
Subject Category
Solar Physics
Accession Number
93A55257
Funding Number(s)
CONTRACT_GRANT: NSF ATM-91-13576
CONTRACT_GRANT: MOESC-03302013
Distribution Limits
Public
Copyright
Other

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