The contribution of kinetic helicity to turbulent magnetic diffusivity

被引：8

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

来源：

ASTRONOMISCHE NACHRICHTEN | 2017年 / 338卷 / 07期

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

页码：790 / 793

页数：4

共 20 条

[1] Scale dependence of alpha effect and turbulent diffusivity [J].

Brandenburg, A. ;

Raedler, K.-H. ;

Schrinner, M. .

ASTRONOMY & ASTROPHYSICS, 2008, 482 (03) :739-746

[2] Magnetic diffusivity tensor and dynamo [J].

Brandenburg, A. ;

Raedler, K. -H. ;

Rheinhardt, M. ;

Kapyla, P. J. .

ASTROPHYSICAL JOURNAL, 2008, 676 (01) :740-751

[3] Turbulence and its parameterization in accretion discs [J].

Brandenburg, A .

ASTRONOMISCHE NACHRICHTEN, 2005, 326 (09) :787-797

[4] The inverse cascade and nonlinear alpha-effect in simulations of isotropic helical hydromagnetic turbulence [J].

Brandenburg, A .

ASTROPHYSICAL JOURNAL, 2001, 550 (02) :824-840

[5]

Brandenburg A, 2008, ASTROPHYS J LETT, V687, pL49, DOI 10.1086/593146

[6] α effect in a family of chaotic flows -: art. no. 034503 [J].

Courvoisier, A ;

Hughes, DW ;

Tobias, SM .

PHYSICAL REVIEW LETTERS, 2006, 96 (03)

[7] NUMERICAL-CALCULATIONS OF FAST DYNAMOS IN SMOOTH VELOCITY-FIELDS WITH REALISTIC DIFFUSION [J].

GALLOWAY, DJ ;

PROCTOR, MRE .

NATURE, 1992, 356 (6371) :691-693

[8] Dynamo coefficients from local simulations of the turbulent ISM [J].

Gressel, O. ;

Ziegler, U. ;

Elstner, D. ;

Ruediger, G. .

ASTRONOMISCHE NACHRICHTEN, 2008, 329 (06) :619-624

[9] A mean-field approach to the propagation of field patterns in stratified magnetorotational turbulence [J].

Gressel, Oliver .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2010, 405 (01) :41-48

[10] QUENCHING AND ANISOTROPY OF HYDROMAGNETIC TURBULENT TRANSPORT [J].

Karak, Bidya Binay ;

Rheinhardt, Matthias ;

Brandenburg, Axel ;

Kapyla, Petri J. ;

Kapyla, Maarit J. .

ASTROPHYSICAL JOURNAL, 2014, 795 (01)

← 1 2 →