| Abstract: | A study is made of the steady-state flow of a viscous conducting incompressible fluid in a half-space, induced by an electric current spreading from a point source on a solid surface. There is a critical finite value of the current at which the velocity on the axis becomes infinite. It is shown that for a high-conductivity medium bifurcation of a new MHD regime with nonzero poloidal field and rotation takes place for arbitrarily large values of the current. The axisymmetric MUD dynamo effect detected does not contradict the Cowling-Braginskii  antidynamo theorem, since the conditions of the theorem are not fulfilled. In the case of low conductivity the paradox can be resolved using the model of an infinitely narrow turbulent jet. Here, too, self-excitation of the field and rotation are detected and their strengthening leads to suppression of the turbulence and relaminarization of the jet.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.2, pp. 4–11, March–April, 1993. |
