HYPOTHETICAL VORTEX-MOTIVE FORCE OR A REALIZATION OF THE TURBULENT VORTEX DYNAMO IN THE TROPICAL ATMOSPHERE
Abstract
The review (Levina et al., 2000) contains a detailed discussion of a series of studies of 1983–1999 related to the creation (1983) and the further development of the mathematical model of a turbulent vortex dynamo. The model was obtained by the methods of the mean-field theory (Krauze and Redler, 1984) and for the first time contained a largescale instability in an electrically non-conducting medium (hydrodynamic alpha effect) generated by the special properties of small-scale helical turbulence of the velocity field. By analogy with the model of the alpha effect in magnetohydrodynamics, such instability is described by a generating term obtained by averaging the equations for the turbulent velocity field and representing a force of some kind in the physical sense. However, unlike the magnetohydrodynamics, where the mean electromotive force acts as the generating term, the interpretation of the result obtained in the model of the hydrodynamic alpha effect caused serious difficulties for a long time. Indeed, the emergence of the mean electromotive force can be explained by the interaction of the magnetic field and the velocity field. In the case of a non-conducting medium, the obtained hypothetical force, for definiteness, let us call it, for example, a “vortex-motive” force, should be created by the velocity field alone. In nature, such force is unknown, but on the basis of new knowledge about atmospheric convection in the tropics, we have been able to interpret the vortex-motive force as a parameterization (Levina, 2018) of the interaction of several effects - rotating deep moist convection (Hendricks et al., 2004), accompanied by intense volumetric heat release, and vertical shear horizontal wind.
The proposed parameterization allows us to explain the implementation of turbulent vortex dynamo in the tropical atmosphere.
This work was supported by the Russian Foundation for Basic Research (RFBR) under Grant 16-05-00551a
References
- Hendricks E.A., Montgomery M.T., and Davis C.A. The role of “vortical” hot towers in the formation of tropical cyclone Diana (1984). J. Atmos. Sci., 2004, Vol. 61, pp. 1209–1232.
- Krauze F. and Redler K.Kh. Magnitnaya gidrodinamika srednikh polei i teoriya dynamo (MeanField Magnetohydrodynamics and Dynamo Theory), Moskva: Mir, 1984, 314 p.
- Levina G.V. On the path from the turbulent vortex dynamo theory to diagnosis of tropical cyclogenesis. Open Journal of Fluid Dynamics, 2018, Vol. 8, pp. 86–114.
- Levina G.V., Moiseev S.S., and Rutkevich P.B. Hydrodynamic alpha-effect in a convective system. Nonlinear Instability, Chaos and Turbulence, Vol. 2, Adv. Fluid Mech. Series, Debnath L. and Riahi D.N. (Eds.), Southampton: WIT Press, 2000, pp. 111–162.
Transfer of copyrights occurs on the basis of a license agreement between the Author and Shirshov Institute of Oceanology, RAS
