Open AccessSolar coronal heating by magnetic cancellation – II. Disconnected and unequal bipoles
Author(s) -
Von Rekowski B.,
Parnell C. E.,
Priest E. R.
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.10345.x
Subject(s) - physics , magnetohydrodynamics , magnetic reconnection , astrophysics , nanoflares , magnetohydrodynamic drive , corona (planetary geology) , coronal loop , magnetic flux , magnetic field , coronal hole , solar wind , computational physics , coronal mass ejection , quantum mechanics , astrobiology , venus
Two‐dimensional numerical magnetohydrodynamic simulations of a cancelling magnetic feature (CMF) and the associated coronal X‐ray bright point (XBP) are presented. Coronal magnetic reconnection is found to produce the Ohmic heating required for a coronal XBP. During the BP phase where reconnection occurs above the base, about 90–95 per cent of the magnetic flux of the converging magnetic bipole cancels at the base. The last ≈5 to 10 per cent of the base magnetic flux is cancelled when reconnection occurs at the base. Reconnection happens in a time‐dependent way in response to the imposed converging footpoint motions. A potential field model gives a good first approximation to the qualitative behaviour of the system, but the magnetohydrodynamics (MHD) experiments reveal several quantitative differences: for example, the effects of plasma inertia and a pressure build‐up in‐between the converging bipole are to delay the onset of coronal reconnection above the base and to lower the maximum X ‐point height.