Formation of buoyant magnetic structures by a localized velocity shear

被引:26
作者
Brummell, N [1 ]
Cline, K
Cattaneo, F
机构
[1] Joint Inst Lab Astrophys, Boulder, CO 80309 USA
[2] Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA
[3] Univ Chicago, Dept Math, Chicago, IL 60637 USA
关键词
MHD; Sun : interior; Sun : magnetic fields; stars : spots;
D O I
10.1046/j.1365-8711.2002.05183.x
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Motivated by considerations of the solar tachocline, we study the generation of strong buoyant magnetic structures by a sheared velocity field localized in a convectively stable background, using non-linear three-dimensional (3D) magnetohydrodynamic (MHD) simulations. The shear flow can spontaneously create strong tube-like toroidal (streamwise) magnetic structures from an imposed weak uniform poloidal (cross-stream) magnetic field. The structures are magnetically buoyant and therefore rise, and may evolve further to a rich variety of geometries, including kinked or arched shapes. The emergence process can repeat indefinitely with a characteristic period. These mechanisms may be relevant to the MHD processes in the solar tachocline and the creation and emergence of solar active regions.
引用
收藏
页码:L73 / U2
页数:6
相关论文
共 29 条
[1]   EMERGING FLUX TUBES IN THE SOLAR CONVECTION ZONE .1. ASYMMETRY, TILT, AND EMERGENCE LATITUDE [J].
CALIGARI, P ;
MORENOINSERTIS, F ;
SCHUSSLER, M .
ASTROPHYSICAL JOURNAL, 1995, 441 (02) :886-902
[2]   BUOYANCY-DRIVEN INSTABILITIES AND THE NONLINEAR BREAKUP OF A SHEARED MAGNETIC LAYER [J].
CATTANEO, F ;
CHIUEH, T ;
HUGHES, DW .
JOURNAL OF FLUID MECHANICS, 1990, 219 :1-&
[3]   THE NONLINEAR BREAKUP OF A MAGNETIC LAYER - INSTABILITY TO INTERCHANGE MODES [J].
CATTANEO, F ;
HUGHES, DW .
JOURNAL OF FLUID MECHANICS, 1988, 196 :323-+
[4]   Solar interface dynamos .2. Linear, kinematic models in spherical geometry [J].
Charbonneau, P ;
MacGregor, KB .
ASTROPHYSICAL JOURNAL, 1997, 486 (01) :502-520
[5]   THE INFLUENCE OF THE CORIOLIS-FORCE ON FLUX TUBES RISING THROUGH THE SOLAR CONVECTION ZONE [J].
CHOUDHURI, AR ;
GILMAN, PA .
ASTROPHYSICAL JOURNAL, 1987, 316 (02) :788-800
[6]   WAVE-PROPAGATION ALONG A MAGNETIC TUBE [J].
DEFOUW, RJ .
ASTROPHYSICAL JOURNAL, 1976, 209 (01) :266-269
[7]   The rise of kink-unstable magnetic flux tubes and the origin of δ-configuration sunspots [J].
Fan, Y ;
Zweibel, EG ;
Linton, MG ;
Fisher, GH .
ASTROPHYSICAL JOURNAL, 1999, 521 (01) :460-477
[8]   THE ORIGIN OF MORPHOLOGICAL ASYMMETRIES IN BIPOLAR ACTIVE REGIONS [J].
FAN, Y ;
FISHER, GH ;
DELUCA, EE .
ASTROPHYSICAL JOURNAL, 1993, 405 (01) :390-401
[9]   WHAT WE KNOW ABOUT THE SUNS INTERNAL-ROTATION FROM SOLAR OSCILLATIONS [J].
GOODE, PR ;
DZIEMBOWSKI, WA ;
KORZENNIK, SG ;
RHODES, EJ .
ASTROPHYSICAL JOURNAL, 1991, 367 (02) :649-657
[10]   The rise of twisted magnetic flux tubes: A high Reynolds number adaptive grid calculation [J].
Hughes, DW ;
Falle, SAEG .
ASTROPHYSICAL JOURNAL, 1998, 509 (01) :L57-L60