[Moments dʼElsässer du troisième ordre en turbulence MHD axisymétrique]
La turbulence MHD incompressible est étudiée en présence dʼun champ magnétique uniforme . Une telle situation est décrite dans lʼespace des corrélations par une relation de divergence qui exprime la conservation statistique du flux dʼénergie dʼElsässer à travers la zone inertielle. Nous faisons lʼansatz que lʼanisotropie, observée quand est suffisamment fort, implique un feuilletage de lʼespace des corrélations. Une conséquence directe est la possibilité dʼobtenir une nouvelle loi vectorielle pour les moments dʼElsässer dʼordre trois qui est paramétrisée par lʼintensité de lʼanisotropie. Nous utilisons lʼhypothèse dʼéquilibre critique pour fixer ce paramètre et trouver une expression unique.
Incompressible MHD turbulence is investigated under the presence of a uniform magnetic field . Such a situation is described in the correlation space by a divergence relation which expresses the statistical conservation of the Elsässer energy flux through the inertial range. The ansatz is made that the development of anisotropy, observed when is strong enough, implies a foliation of space correlation. A direct consequence is the possibility to derive a vectorial law for third-order Elsässer moments which is parametrized by the intensity of anisotropy. We use the so-called critical balance assumption to fix this parameter and find a unique expression.
Mot clés : MHD, Turbulence, Vent solaire
Sébastien Galtier 1, 2
@article{CRPHYS_2011__12_2_151_0, author = {S\'ebastien Galtier}, title = {Third-order {Els\"asser} moments in axisymmetric {MHD} turbulence}, journal = {Comptes Rendus. Physique}, pages = {151--159}, publisher = {Elsevier}, volume = {12}, number = {2}, year = {2011}, doi = {10.1016/j.crhy.2010.11.006}, language = {en}, }
Sébastien Galtier. Third-order Elsässer moments in axisymmetric MHD turbulence. Comptes Rendus. Physique, Volume 12 (2011) no. 2, pp. 151-159. doi : 10.1016/j.crhy.2010.11.006. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2010.11.006/
[1] Turbulence: The Legacy of A.N. Kolmogorov, Cambridge University Press, Cambridge, 1995
[2] Dissipation of energy in locally isotropic turbulence, Dokl. Akad. Nauk SSSR, Volume 32 (1941), pp. 16-18
[3] , Statistical Fluid Mechanics, vol. 2, MIT Press, Cambridge MA, 1975
[4] Local structure of the temperature field in a turbulent flow, Dokl. Akad. Nauk SSSR, Volume 69 (1949), pp. 743-746
[5] Dynamical length scales for turbulent magnetized flows, Geophys. Res. Lett., Volume 25 (1998), pp. 273-276
[6] Exact scaling laws for 3D electron MHD turbulence, J. Geophys. Res., Volume 113 (2008), p. A01102
[7] von Kármán–Howarth equations for Hall magnetohydrodynamic flows, Phys. Rev. E, Volume 77 (2008), p. 015302(R)
[8] Exact vectorial law for axisymmetric MHD turbulence, Astrophys. J., Volume 704 (2009), pp. 1371-1384
[9] Consequence of space correlation foliation for EMHD turbulence, Phys. Plasmas, Volume 16 (2009), p. 112310
[10] Turbulence of a conducting fluid in a strong magnetic field, Sov. Astron., Volume 7 (1964), pp. 566-571
[11] Inertial-range spectrum of hydromagnetic turbulence, Phys. Fluids, Volume 8 (1965), pp. 1385-1387
[12] et al. A weak turbulence theory for incompressible MHD, J. Plasma Phys., Volume 63 (2000), pp. 447-488
[13] The anisotropy of MHD Alfvénic turbulence, Astrophys. J., Volume 539 (2000), pp. 273-282
[14] Spectrum of magnetohydrodynamic turbulence, Phys. Rev. Lett., Volume 96 (2006), p. 115002
[15] Turbulent cascades, transfer, and scale interactions in MHD, New J. Phys., Volume 9 (2007), pp. 298-318
[16] et al. Anisotropic fluxes and nonlocal interactions in MHD turbulence, Phys. Rev. E, Volume 76 (2007), p. 056313
[17] Energy decay laws in strongly anisotropic MHD turbulence, Phys. Rev. Lett., Volume 100 (2008), p. 074502
[18] Development of anisotropy in incompressible MHD turbulence, Phys. Rev. E, Volume 78 (2008), p. 066301
[19] Toward a theory of interstellar turbulence. II. Strong alfvénic turbulence, Astrophys. J., Volume 438 (1995), pp. 763-775
[20] On spectral scaling laws for incompressible anisotropic MHD turbulence, Phys. Plasmas, Volume 12 (2005), p. 092310
[21] Simulations of incompressible MHD turbulence, Astrophys. J., Volume 554 (2001), pp. 1175-1196
[22] et al. Local anisotropy in incompressible MHD turbulence, Phys. Plasmas, Volume 8 (2001), pp. 2673-2681
[23] et al. Anisotropic fluid turbulence in the interstellar medium and solar wind, Phys. Plasmas, Volume 10 (2003), pp. 1954-1962
[24] Anisotropic form of third-order moments and relationship to the cascade rate in axisymmetric MHD turbulence, Phys. Plasmas, Volume 14 (2007), p. 092305
[25] Wave turbulence in incompressible Hall MHD, J. Plasma Phys., Volume 72 (2006), pp. 721-769
[26] Wave turbulence in magnetized plasmas, Nonlin. Processes Geophys., Volume 16 (2009), pp. 83-98
[27] et al. Anisotropy and minimum variance of MHD fluctuations in the inner heliosphere, J. Geophys. Res., Volume 98 (1993), pp. 17461-17466
[28] Dominant two-dimensional solar wind turbulence with implications for cosmic ray transport, J. Geophys. Res., Volume 101 (1996), pp. 2511-2522
[29] et al. Observation of inertial energy cascade in interplanetary space plasma, Phys. Rev. Lett., Volume 99 (2007), p. 115001
[30] et al. Scaling laws of turbulence and heating of fast solar wind: the role of density fluctuations, Phys. Rev. Lett., Volume 103 (2009), p. 061102
[31] et al. Heating the solar wind by a MHD turbulent energy cascade, Astrophys. J., Volume 677 (2008), p. L71-L74
[32] et al. Analogy between predictions of Kolmogorov and Yaglom, J. Fluid Mech., Volume 332 (1997), pp. 395-409
[33] Small-scale structures in three-dimensional MHD turbulence, Phys. Rev. Lett., Volume 97 (2006), p. 244503
[34] et al. Scale-dependent angle of alignment between velocity and magnetic field fluctuations in solar wind turbulence, J. Geophys. Res., Volume 114 (2008), p. A01107
Cité par Sources :
Commentaires - Politique