RESISTIVE DRIFT-WAVE TURBULENCE

Two-dimensional resistive drift-wave turbulence is studied by high-resolution numerical simulations in the limit of small viscosity. Density and potential fluctuations are cross-coupled by resistive dissipation, proportional to the adiabaticity parameter, script c sign, which determines the character of the system: adiabatic (script c sign≫1) or hydrodynamic (script c sign≪1). Various cases are computed for 0.1≤script c sign≤5. Energy spectra exhibit a maximum at some wave number k0(script c sign) and an inertial range behavior for k>k0. The transfer of energy and vorticity is directly computed and confirms the persistence of local cascade dynamics in all regimes: the familiar dual cascade for the E x B flow eddies, and the direct cascade to small scales for the density as it is advected by the eddies. Inertial range spectral power laws agree surprisingly well with simple scaling predictions. No prominent large-scale long-lived coherent structures are observed, an absence that is consistent with the statistical properties, which are found to be perfectly Gaussian for k≲k0, but exhibit the non-Gaussian behavior, typical for small-scale intermittency, in the inertial range. © 1995 American Institute of Physics.