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The singular points in steady state, field-aligned plasma transport models based on velocity moment theory are examined. In particular, two separate singular points in the equations obtained from the 16-moment approximation are identified. These equations are presented in a form that makes the singularities apparent, and they are solved in a simple illustrative case. The singular points, one occurring at the sonic point and the other at a critical value of the parallel heat flux, give rise to different outflow regimes, characterized generically by different asymptotic behavior. The existence of the different outflow regimes separated by the heat flux critical point has been only hinted at in previous discussions of numerical simulation of the polar wind.

Experimental data obtained in Tokamaks heated by NBI or ECRH provides increasing evidence for a beta limit given by p(%) = gI(MA)/a(m)B(T) with g=2.5-3.S. Steady-state operation at about 80% of this limit appears possible. Ideal MHD numerical optimisations suggest that higher values are possible with optimised current profiles in circular plasmas, approaching at low current the value calculated analytically by Wesson and Sykes(1985). At elongations around 2 there is evidcnce of a change in the scaling law giving p in terms of the current in the region of low q.

The quasilinear equations are derived for an inhomogeneous magnetized plasma without using the random phase approximation and the expansion in the ratio of the Larmor radius to the inhomogeneity scale. The equations take into account both resonant and nonresonant interactions, and possess the necessary conservation properties.

A mechanism, in which the wave induced flux plays the key role, is proposed to explain the density rise observed during Alfven wave heating in the TCA tokamak.

The adiabatic interaction of low‐frequency ion‐acoustic‐like perturbations with high‐frequency ion‐acoustic turbulence is studied. The turbulence is found to become unstable provided certain conditions are met. These conditions are derived explicitly.

The equations of quasilinear theory are derived for a uniformly magnetized inhomogeneous plasma interacting with electromagnetic field fluctuations. The derivation avoids the use of the random phase approximation, and requires no assumption on the ratio of the Larmor radius to the fluctuation wavelength. These equations are used to obtain the transport equations for each plasma component. The latter satisfy the necessary conservation properties, and yield explicit expressions for various fluxes.