Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 995-1004 |
| Number of pages | 10 |
| Journal | Astronomy and Astrophysics |
| Volume | 507 |
| Issue number | 2 |
| DOIs | |
| State | Published - Nov 2009 |
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On the emergence of toroidal flux tubes : general dynamics and comparisons with the cylinder model. / MacTaggart, David; Hood, Alan W.
In: Astronomy and Astrophysics, Vol. 507, No. 2, 11.2009, p. 995-1004.Research output: Contribution to journal › Article
TY - JOUR
T1 - On the emergence of toroidal flux tubes
T2 - Astronomy and Astrophysics
AU - MacTaggart,David
AU - Hood,Alan W.
PY - 2009/11
Y1 - 2009/11
N2 - Aims. In this paper we study the dynamics of toroidal flux tubes emerging from the solar interior, through the photosphere and into the corona. Many previous theoretical studies of flux emergence use a twisted cylindrical tube in the solar interior as the initial condition. Important insights can be gained from this model, however, it does have shortcomings. The axis of the tube never fully emerges as dense plasma becomes trapped in magnetic dips and restrains its ascent. Also, since the entire tube is buoyant, the main photospheric footpoints (sunspots) continually drift apart. These problems make it difficult to produce a convincing sunspot pair.We aim to address these problems by considering a different initial condition, namely a toroidal flux tube. Methods. We perform numerical experiments and solve the 3D MHD equations. The dynamics are investigated through a range of initial field strengths and twists. Results. The experiments demonstrate that the emergence of toroidal flux tubes is highly dynamic and exhibits a rich variety of behaviour. In answer to the aims, however, if the initial field strength is strong enough, the axis of the tube can fully emerge. Also, the sunspot pair does not continually drift apart. Instead, its maximum separation is the diameter of the original toroidal tube.
AB - Aims. In this paper we study the dynamics of toroidal flux tubes emerging from the solar interior, through the photosphere and into the corona. Many previous theoretical studies of flux emergence use a twisted cylindrical tube in the solar interior as the initial condition. Important insights can be gained from this model, however, it does have shortcomings. The axis of the tube never fully emerges as dense plasma becomes trapped in magnetic dips and restrains its ascent. Also, since the entire tube is buoyant, the main photospheric footpoints (sunspots) continually drift apart. These problems make it difficult to produce a convincing sunspot pair.We aim to address these problems by considering a different initial condition, namely a toroidal flux tube. Methods. We perform numerical experiments and solve the 3D MHD equations. The dynamics are investigated through a range of initial field strengths and twists. Results. The experiments demonstrate that the emergence of toroidal flux tubes is highly dynamic and exhibits a rich variety of behaviour. In answer to the aims, however, if the initial field strength is strong enough, the axis of the tube can fully emerge. Also, the sunspot pair does not continually drift apart. Instead, its maximum separation is the diameter of the original toroidal tube.
U2 - 10.1051/0004-6361/200912930
DO - 10.1051/0004-6361/200912930
M3 - Article
VL - 507
SP - 995
EP - 1004
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
IS - 2
ER -