LARGE-SCALE HYDROMAGNETIC DYNAMO BY LEHNERT WAVES IN NONRESISTIVE PLASMA

A new mechanism of large-scale magnetic fields generation is studied, which is based on creation of mean electromotive force through interactions between distinct Lehnert (magneto-Coriolis) waves. The crucial feature of this mechanism is that it does not require magnetic diffusivity to operate, in contrast to the hitherto known standard diffusive one. The hydromagnetic dynamo problem is studied at a fundamental level, with nonstationary spectrum tensor of the underlying turbulence, and the obtained results are discussed in the context of the standard theory of large-scale magnetic field generation. The significance of the new mechanism is found to manifest itself at E-eta << Rm(-3/4) where E-eta is the modified Ekman number based on magnetic diffusivity and Rm >> 1 denotes the magnetic Reynolds number.