Quasilinear theory of electron transport by radio frequency waves and nonaxisymmetric perturbations in toroidal plasmas

Psfc/ja-08-38 Quasilinear Theory of Electron Transport by Radio Frequency Waves and Non-axisymmetric Perturbations in Toroidal Plasmas

The use of radio frequency (RF) waves to generate plasma current and to modify the current profile in magnetically confined fusion devices is well documented. The current is generated by the interaction of electrons with an appropriately tailored spectrum of externally launched RF waves. In theoretical and computational studies, the interaction of RF waves with electrons is represented by a qua...

Psfc/ja-08-37 Quasilinear Theory for Momentum and Spatial Diffusion Due to Radio Frequency Waves in Non-axisymmetric Toroidal Plasmas

Physics of Electron Internal Transport Barrier in Toroidal Helical Plasmas

The role of zonal flows in the formation of the transport barrier in the helical plasmas is analyzed using the transport code. A set of one-dimensional transport equations is analyzed, including the effect of zonal flows. The turbulent transport coefficient is shown to be suppressed when the plasma state changes from the weak negative radial electric field to the strong positive one. This bifur...

Numerical solution of quasilinear kinetic diffusion equations in toroidal plasmas

One of the main challenges for the realization of a working fusion power plant is an increased detailed understanding of kinetic phenomena in toroidal plasmas. The tokamak is a toroidal, magnetically confined plasma device and is currently the main line towards a power plant. The spatial and temporal scales in a tokamak plasma are extreme and the only tractable path for quantitative studies is ...

Neoclassical Transport in Enhanced Confinement Toroidal Plasmas

It has recently been reported that ion thermal transport levels in enhanced confinement tokamak plasmas have been observed to fall below the "irreducible minimum level" predicted by standard neoclassical theory. This apparent contradiction is resolved in the present analysis by relaxing the basic neoclassical assumption that the ions orbital excursions are much smaller than the local toroidal m...