STATISTICAL DYNAMICS OF DISSIPATIVE DRIFT WAVE TURBULENCE

The statistical dynamics of a two-field model of dissipative drift wave turbulence is investigated using the EDQNM (eddy damped quasinormal Markovian) closure method [J. Fluid Mech. 41, 363 (1970)]. The analyses include studies of statistical closure equations, derivation of an H theorem, and its application to formulation of selective decay hypotheses for turbulent relaxation process. The results show that the dynamics of the two-field model is fundamentally different from that of the familiar, one-field Hasegawa-Mima model [Phys. Fluids 21, 87 (1978)]. In particular, density fluctuations nonlinearly couple to small scales, as does enstrophy. This transfer process is nonlinearly regulated by the dynamics of the density-vorticity cross correlation. Since density perturbations are not simply related to potential perturbations, as is vorticity, their transfer rate is greater. As a result, turbulent relaxation processes exhibit both dynamic alignment of density and vorticity and coherent vortex formation.