Two-dimensional numerical simulation of trapped ion mode and drift wave turbulence

The first chapter is the paper entitled "Two-dimensional numerical simulation of trapped electron mode turbulent transport in a tokamak". Trapped electrons are lumped into hot and cold fluids to treat temperature gradient effects. The ion temperature gradient and dissipative trapped electron modes were simultaneously present. A plasma particle pinch was found only at extremely low collisionalities and a heat conduction pinch was found at moderate collisionalities, although there was no energy flow pinch seen.; The second chapter is the paper entitled "Two-dimensional numerical simulation of trapped ion mode turbulence in a tokamak". The simulation of long wavelength trapped ion mode turbulence was used to investigate Bohm (macroscopic) versus gyro-Bohm (microscopic) scaling behavior in tokamaks. A nonlinear two-field model of dissipative trapped ion turbulence evolving trapped ion and trapped electron density fluctuations showed gyro-Bohm-like scaling in contrast to earlier simulation work by Saison, Wimmel, and Sardei (Plasma Physics, Vol. 20, pp. 1 to 20, 1978). In fact nearly all features of trapped ion mode turbulence and transport originally posited by Kadomstev and Pogutse (Reviews of Plasma Physics, Vol. 5) were recovered.; The third chapter is the paper entitled "Numerical simulation of drift waves and trapped ion modes". Simulations were used to study the interaction of trapped electron drift waves (DW) and trapped ion modes (TIM). Wavenumber (k) space was divided into long wave and short wave regions at a poloidal wavenumber corresponding to the ion bounce frequency. Two field models were used to describe trapped electron drift wave dynamics at short waves and trapped ion mode dynamics for long waves. The principal result of this study was that the TIM did not contribute to the diffusion significantly, regardless of the model for the nonlinear coupling to the DW.; The appendix documents a sparsely populated k-space grid scheme that was invented to perform the TIM/DW simulations. The method did not give physical results and was not used. The argument in the appendix states that it is not possible to mock up the nonlinear convolutions in Fourier representation such that some of the modes need not be included.