WHAT IS A STELLAR DYNAMO

被引:15
作者
CATTANEO, F
HUGHES, DW
WEISS, NO
机构
[1] UNIV LEEDS,DEPT APPL MATH STUDIES,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND
[2] UNIV CAMBRIDGE,DEPT APPL MATH & THEORET PHYS,CAMBRIDGE CB3 9EW,ENGLAND
关键词
D O I
10.1093/mnras/253.3.479
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Numerical simulations of turbulent stellar dynamos are now feasible. The characteristic time-scale for kinematic behaviour is related to the turnover time of the turbulent eddies. Results from idealized two-dimensional models show that the Lorentz force alters the velocity field, allowing transient magnetic activity to persist for intervals much longer than the expected turbulent decay time. For three-dimensional flows we define a characteristic time T(e) for turbulent diffusion to act, based on the rate at which magnetic energy is dissipated, and assert that there is a dynamo only if the field survives for times much longer than T(e). This criterion is then applied to cyclic magnetic activity in late-type stars.
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页码:479 / 484
页数:6
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