Resistive drift wave and interchange turbulence in a cylindrical plasma with magnetic and velocity shear
- Plasma Physics Laboratory, Kyoto University, Gokasho, Uji 611 (Japan)
- National Institute for Fusion Science, Furoh-cho, Chigusa, Nagoya 464 (Japan)
- Department of Communication Engineering, Osaka University, Osaka 565 (Japan)
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}{sub {ital e}}/{nu}{sub {ital e}})({rho}{sub {ital s}}{sup 2}/{ital R}{sup 2})/({kappa}{rho}{sub {ital 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}{sub {ital e}}{sup (1/3)}. Here {ital R} is the major radius, {rho}{sub {ital s}} is the ion Larmor radius at the electron temperature, {Omega}{sub {ital e}} is the electron cyclotron frequency, {nu}{sub {ital 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/{ital R}. For large ({Omega}{sub {ital e}}/{nu}{sub {ital e}})({rho}{sub {ital s}}{sup 2}/{ital R}{sup 2})/({kappa}{rho}{sub {ital s}}), the electrons become adiabatic, with a significantly reduced particle flux proportional to {nu}{sub {ital e}}. In the presence of an externally imposed radial electric field with a negative (positive) polarity, {ital E}{sub {ital r}}{lt}0 ({ital E}{sub {ital r}}{gt}0), the poloidal velocity shear in the {bold E}{times}{bold B} 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.
- OSTI ID:
- 7285288
- Journal Information:
- Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 4:7; ISSN 0899-8221; ISSN PFBPE
- Country of Publication:
- United States
- Language:
- English
Similar Records
Rotation shear induced fluctuation decorrelation in a toroidal plasma
Effects of a nonuniform equilibrium electric field on ion temperature gradient instabilities