Suppression of turbulent transport by a weak magnetic field

Cattaneo, Fausto; Ваинштейн, С. И.

doi:10.1086/186093

Cited by 213 publications

(223 citation statements)

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“…The full twodimensional MHD result can be obtained by taking the limit in equation (22), which will reproduce equation B 0 ] 0 (1). This agrees with the well-known result on the suppression of Ñux di †usion in two-dimensions (Cattaneo & Vainshtein 1991 ;Gruzinov & Diamond 1994). …”

Section: Fluctuations From Equationssupporting

confidence: 92%

“…The turbulent di †usivity that we obtained generalizes g eff the two-dimensional MHD result (Cattaneo & Vainshtein 1991 ;Gruzinov & Diamond 1994) (1 ] Re m ReSb2T/Su2T) D g/2 The two-dimensional result can simply be recovered from our results on the Ñux by taking the limit…”

Section: Conclusion and Discussionsupporting

confidence: 66%

“…Bhattacharjee & Yuan 1995). Equation (22) is the Ñux in three-dimensional RMHD, which generalizes the two-dimensional MHD result (Cattaneo & Vainshtein 1991 ;Gruzinov & Diamond 1994). Several aspects of this result are of interest.…”

Section: Fluctuations From Equationsmentioning

confidence: 77%

“…where SBT is the large-scale magnetic Ðeld and Su2T the turbulent kinetic energy (Cattaneo & Vainshtein 1991 ;Gruzinov & Diamond 1994). The above expression implies that even a weak magnetic Ðeld (i.e., one far below the equipartition value Sb2T D Su2T) is potentially important.…”

Section: Introductionmentioning

confidence: 99%

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On Turbulent Reconnection

Kim

Diamond

2001

ApJ

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We examine the dynamics of turbulent reconnection in two-dimensional and three-dimensional reduced MHD by calculating the e †ective dissipation due to coupling between small-scale Ñuctuations and large-scale magnetic Ðelds. Sweet-Parker type balance relations are then used to calculate the global reconnection rate. Two approaches are employedÈquasi-linear closure and an eddy-damped Ñuid model. Results indicate that despite the presence of turbulence, the reconnection rate remains inversely proportional to as in the Sweet-Parker analysis. In two-dimensions, the global reconnection rate is JRe m , shown to be enhanced over the Sweet-Parker result by a factor of magnetic Mach number. These results are the consequences of the constraint imposed on the global reconnection rate by the requirement of mean-square magnetic potential balance. The incompatibility of turbulent Ñuid-magnetic energy equipartition and stationarity of mean-square magnetic potential is demonstrated.

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Section: Fluctuations From Equationssupporting

confidence: 92%

Section: Conclusion and Discussionsupporting

confidence: 66%

Section: Fluctuations From Equationsmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

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On Turbulent Reconnection

Kim

Diamond

2001

ApJ

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“…A clear understanding of the generation and dynamics of magnetic fields is important to astrophysics in many ways. Unfortunately, their dynamics has not been well understood, at least judging by the diversity of opinions found in the literature [20,66,50,80,16]. Consequently, arguments which cite magnetic fields as a dynamically important element in any particular object have tended to rely on phenomenology, rather than any sort of fundamental explanation.…”

Section: Introductionmentioning

confidence: 99%

Problems and Progress in Astrophysical Dynamos

Vishniac

Lazarían²,

Cho³

Turbulence and Magnetic Fields in Astrophysics

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Abstract. Astrophysical objects with negligible resistivity are often threaded by large scale magnetic fields. The generation of these fields is somewhat mysterious, since a magnetic field in a perfectly conducting fluid cannot change the flux threading a fluid element, or the field topology. Classical dynamo theory evades this limit by assuming that magnetic reconnection is fast, even for vanishing resistivity, and that the large scale field can be generated by the action of kinetic helicity. Both these claims have been severely criticized, and the latter appears to conflict with strong theoretical arguments based on magnetic helicity conservation and a series of numerical simulations. Here we discuss recent efforts to explain fast magnetic reconnection through the topological effects of a weak stochastic magnetic field component. We also show how mean-field dynamo theory can be recast in a form which respects magnetic helicity conservation, and how this changes our understanding of astrophysical dynamos. Finally, we comment briefly on why an asymmetry between small scale magnetic and velocity fields is necessary for dynamo action, and how it can arise naturally.

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Sunspot decay as a test of the eta-quenching concept

Rüdiger¹,

Kitchatinov²

2000

Astron. Nachr.

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Suppression of turbulent transport by a weak magnetic field

Cited by 213 publications

References 0 publications

On Turbulent Reconnection

On Turbulent Reconnection

Problems and Progress in Astrophysical Dynamos

Sunspot decay as a test of the eta-quenching concept

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