RESISTIVE DRIFT WAVE AND INTERCHANGE TURBULENCE IN A CYLINDRICAL PLASMA WITH MAGNETIC AND VELOCITY SHEAR

By solving numerically the two-field nonlinear model equations for the potential and density fluctuations in the presence of a density gradient, magnetic curvature with shear, and poloidal velocity shear, turbulent spectra and diffusion rates are studied. When the adiabatic parameter (OMEGA(e)/nu(e)) (rho(s)2/R2)/(kappa-rho(s)) is small, a trend of a dual cascade, normal cascade of the density fluctuations, and an inverse cascade of the potential fluctuations, is seen in the wave-number spectra, producing a large particle flux proportional to nu(e)1/3. Here R is the major radius, rho(s) is the ion Larmor radius at the electron temperature, OMEGA(e) is the electron cyclotron frequency, nu(e) is the electron-ion collision frequency, and kappa is an inverse scale length of the background density gradient. Parallel wave numbers are represented by 1/R. For large (OMEGA(e)/nu(e)) (rho(s)2/R2)/(kappa-rho(s)), the electrons become adiabatic, with a significantly reduced particle flux proportional to nu(e). In the presence of an externally imposed radial electric field with a negative (positive) polarity, E(r)<0 (E(r)>0), the poloidal velocity shear in the EXB drift motion suppresses (enhances) the fluctuation level in the growth phase; however, these effects practically disappear in the saturated state. The radial electric field produced by the inverse cascade due to the convective nonlinearity is also studied; however, its effect on the particle transport is mild.