The critical role of magnetic helicity in astrophysical large-scale dynamos

被引：18
|
作者：
Brandenburg, Axel [1 ,2 ]
机构：
[1] NORDITA, S-10691 Stockholm, Sweden
[2] Stockholm Univ, Dept Astron, S-10691 Stockholm, Sweden
来源：
PLASMA PHYSICS AND CONTROLLED FUSION | 2009年 / 51卷 / 12期
关键词：
REVERSED-FIELD PINCH; ALPHA-OMEGA-DYNAMO; MAGNETOHYDRODYNAMIC TURBULENCE; INVERSE CASCADE; SIMULATIONS; DIFFUSIVITY; GENERATION; FLUX;
D O I：
10.1088/0741-3335/51/12/124043
中图分类号：
O35 [流体力学]; O53 [等离子体物理学];
学科分类号：
070204 ; 080103 ; 080704 ;
摘要：
The role of magnetic helicity in astrophysical large-scale dynamos is reviewed and compared with cases where there is no energy supply and an initial magnetic field can only decay. In both cases magnetic energy tends to get redistributed to larger scales. Depending on the efficiency of magnetic helicity fluxes the decay of a helical field can speed up. Likewise, the saturation of a helical dynamo can speed up through magnetic helicity fluxes. The astrophysical importance of these processes is reviewed in the context of the solar dynamo and an estimated upper limit for the magnetic helicity flux of 10(46) Mx(2)/cycle is given.
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页数：12
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