We consider the microscopic sources of toroidal and poloidal flow in confined magnetoplasmas and the effects of such flows on macroscopic stability. The central difficulty is satisfactory modelling of kinetic theory effects so as to permit their robust introduction into magnetohydrodynamic (MHD) codes. It is tentatively concluded that poloidal rotation, but not toroidal, is responsible for the computed stabilization and return to axisymmetry.

The thermal mean-field equilibrium of a translation-invariant, unbounded one- component guiding-centre plasma is studied by analytical techniques. A variational principle is constructed. It is shown that only radial symmetric, decreasing density profiles occur. Prescribing the total number of gyro centres N ∈ (0, ∞), the energy E ∈ (E0, ∞) and the canonical angular momentum M ∈ (0, ∞]) uniquely determines a profile. Metastable or unstable profiles do not exist. A simple algebraic relation between N, M, the guiding-centre temperature β−1 and the characteristic Larmor frequency ω is derived. This explains Williamson's computer-based observations.

A semi-analytical approach is proposed for computing the non-local response of a toroidal plasma to an electromagnetic perturbation. Although the perturbed distribution function as well as the absorbed power are also computed, the focus is on the associated quasi-linear diffusion operator. Different decorrelation models allow one to recapture the well-known ideal collisionless plasma result where the wave–particle energy exchange is exactly at resonance, as well as the more realistic plasma response where the interaction region is widened. The choice of the independent variables also allows one to carry out all computations except the integration of the guiding-centre motion analytically.

A new mechanism is suggested that draws non-resonant thermal electrons into a higher-velocity range, where they can be effectively accelerated by waves. We argue that the acceleration of a small number of pre-existing resonant particles influences the dynamics of the bulk plasma and results in a macroscopic electric field. The solution for the spatial dependence of this electric field is obtained, and it appears to be a new type of electrostatic shock, which forms only in the presence of background turbulence. This field enriches the region of resonant particles with thermal electrons, which leads to a build-up of an excess of accelerated particles. The number of accelerated particles is calculated. This mechanism appears as a good candidate to explain electron acceleration in the foot of quasi-perpendicular shocks.

A new model for collisional transport in a tokamak plasma is analysed. This model is obtained from Grad's 2-fluid 13-moment equations by estimating the order of magnitude of the various effects and neglecting those that are small. The model includes small particle flows, pressure anisotropy and temperature variation within flux surfaces. A formal solution is calculated that satisfies the model equations to O(me/mi). These solutions are found to evolve on a time scale Temi/me ≈ 50 ms.

The Saha equilibrium approximation and the temperature relaxation approximation to the MHD equations are investigated with regard to the analysis of the formation of nonlinear ionization non-uniformities and their evolution in a non- equilibrium MHD plasma. An analysis of characteristic relaxation times under typical plasma parameters is carried out to verify these approximations. Characteristic space scales of electron thermal conductivity and radiation are evaluated. These space scales determine the characteristic width of nonlinear ionization wave fronts, and are important for the application of numerical simulations.

A gyrating electron beam propagating through a planar plasma duct can excite a whistler wave or an electron-cyclotron wave, depending on the plasma- density profile of the duct and the energy of the beam. The gyrational motion of the electron beam supplies energy to the wave. In the case of a whistler wave the interaction occurs via coupling of the fast cyclotron beam mode (ω ≈ k2vb + ωc/γ0) to the electromagnetic whistler mode through the Weibel instability mechanism, whereas for an electron-cyclotron wave the coupling is through the negative-mass instability mechanism. It is seen that there exist two diflerent beam-energy regimes for excitation of these waves. The growth rate and the efficiency of conversion for both waves are calculated for typical parameters of a gyrotron and a large-orbit gyrotron.