The contribution of kinetic helicity to turbulent magnetic diffusivity

被引:7
|
作者
Brandenburg, A. [1 ,2 ,3 ,4 ,5 ,6 ]
Schober, J. [4 ,5 ]
Rogachevskii, I. [1 ,4 ,5 ,7 ]
机构
[1] Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA
[2] Univ Colorado, JILA, Boulder, CO 80309 USA
[3] Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA
[4] KTH Royal Inst Technol, NORDITA, S-10691 Stockholm, Sweden
[5] Stockholm Univ, S-10691 Stockholm, Sweden
[6] Stockholm Univ, AlbaNova Univ Ctr, Dept Astron, Stockholm, Sweden
[7] Ben Gurion Univ Negev, Dept Mech Engn, Beer Sheva, Israel
基金
美国国家科学基金会;
关键词
magnetic fields; magnetohydrodynamics (MHD); turbulence; ROTATING MAGNETOCONVECTION; SIMULATIONS; ALPHA; GEODYNAMO; DYNAMO;
D O I
10.1002/asna.201713384
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Using numerical simulations of forced turbulence, we show that for magnetic Reynolds numbers larger than unity, that is, beyond the regime of quasilinear theory, the turbulent magnetic diffusivity attains an additional negative contribution that is quadratic in the kinetic helicity. In particular, for large magnetic Reynolds numbers, the turbulent magnetic diffusivity without helicity is about twice the value with helicity. Such a contribution was not previously anticipated, but, as we discuss, it turns out to be important when accurate estimates of the turbulent magnetic diffusivity are needed.
引用
收藏
页码:790 / 793
页数:4
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