Development of twist in an emerging magnetic flux tube by poloidal field accretion

Details Development of twist in an emerging magnetic flux tube by poloidal field accretion Development of twist in an emerging magnetic flux tube by poloidal field accretion

2005-12-19

arxiv.org/abs/astro-ph/0512472v1

Astron.Astrophys. 449 (2006) 781-789

Astronomy and Astrophysics

Astrophysics

9 pages, 7 figures. A&A, in press

Scientific paper

10.1051/0004-6361:20054401

Following an earlier proposal by Choudhuri (2003) for the origin of twist in the magnetic fields of solar active regions, we model the penetration of a wrapped up background poloidal field into a toroidal magnetic flux tube rising through the solar convective zone. The rise of the straight, cylindrical flux tube is followed by numerically solving the induction equation in a comoving Lagrangian frame, while an external poloidal magnetic field is assumed to be radially advected onto the tube with a speed corresponding to the rise velocity. One prediction of our model is the existence of a ring of reverse current helicity on the periphery of active regions. On the other hand, the amplitude of the resulting twist depends sensitively on the assumed structure (diffuse vs. concentrated/intermittent) of the active region magnetic field right before its emergence, and on the assumed vertical profile of the poloidal field. Nevertheless, in the model with the most plausible choice of assumptions a mean twist comparable to the observations can result rather naturally. Our results indicate that the contribution of this mechanism to the twist can be quite significant, and under favourable circumstances it can potentially account for most of the current helicity observed in active regions.

Affiliated with

Also associated with

No associations

Rating

Development of twist in an emerging magnetic flux tube by poloidal field accretion does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Development of twist in an emerging magnetic flux tube by poloidal field accretion, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Development of twist in an emerging magnetic flux tube by poloidal field accretion will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-280967