The problem of the wave fields excited by a gap source at the edge of an inhomogeneous, magnetized plasma with a pair of lower-hybrid resonance layers present and bounded by conducting walls is solved. The approach used is that of a solution as a sum of multiply-reflected extraordinary mode and ion-thermal resonance cones as an alternative to the guided-wave mode approach. This is achieved by dividing up the plasma into cross-sections where WKB solutions are valid, and into lower-hybrid resonance layers where asymptotic methods are employed and connexion coefficients between each region are obtained. A diagrammatic scheme for writing the solution is introduced which can in principle be used to write down the solution for any problem of this general type once the connexion coefficients across a resonance layer have been determined via asymptotic analysis. This allows a determination in great detail of the structure and properties of the resonance cones in our model and the way they transform across the back-to-back hybrid layers. Evanescent resonance cones are found to exist in the high-density region between the hybrid resonance layers and tunnel through to the other side, maintaining their general structure if the layer is relatively thin.

A statistical procedure is applied for constructing an entropy functional associated with a collective Vlasov equilibrium described by a given coarse-grained current and charge distribution. The functional is not at a maximum if the magnetic or electrostatic equilibrium is not unique. This property connects the principle of maximum entropy with bifurcation theory and marginal stability analysis.

The stability of collisionless reconnecting modes which are driven by a current density gradient is analysed. We consider an inhomogeneous plasma embedded in a sheared magnetic field with finite density and temperature gradients and employ a kinetic description for the inner boundary layer. Appropriate approximations reduce the resulting integro-differential system of equations to a pair of coupled second-order differential equations. In contrast to previous results, the differential operators acting on the field components do not exhibit definite symmetry. Matching is performed numerically to the outer ideal MHD region without regard to symmetry. The asymmetric part of the solution affects the mode frequency and growth rate to the extent that the radial amplitude of the perturbed magnetic field has a significant variation within the singular layer. Stability properties with respect to relevant parameters are investigated.

This paper gives an extensive characterization of the range of validity of the Compton and Raman approximations to the exact free electron laser dispersion relation for a cold, relativistic electron beam propagating through a constantamplitude helical wiggler magnetic field. The electron beam is treated as infinite in transverse extent. Specific properties of the exact and approximate dispersion relations are investigated analytically and numerically. In particular, a detailed numerical analysis is carried out to determine the range of validity of the Compton approximation.

The motion of a plasmoid (plasma-field entity) across an inhomogeneous magnetic field distribution of which the direction and strength change along the penetration trajectory has been studied. The bulk velocity decreases when the plasma element penetrates into a region of increasing magnetic field. The critical magnetic field intensity where a plasmoid is stopped or deflected is found to be the same critical field as that which has been observed in laboratory experiments for a non-rotating B-field distribution. The polarization electric field induced inside a moving plasma element has been determined for both low-β and high-β plasmoids. The momentum density vector of a plasmoid is deflected in the – B × ∇B and – B × (B. ∇)B directions as it penetrates into an inhomogeneous B-field distribution. This kinetic model has been applied to the impulsive penetration of solar wind plasma irregularities impinging on the earth's geomagnetic field with an excess momentum density. As a consequence of impulsive penetration, a plasma boundary layer is formed where the intruding plasmoids are deflected eastward. Magnetospheric plasma is dragged in the direction parallel to the flanks of the average magnetopause surface. Diamagnetic effects of these impulsively penetrating plasmoids into the magnetosphere are also briefly discussed.

The instability of low-frequency waves in a cold plasma mixed with hot electrons is investigated using the first-order CGL equations for electrons. It is assumed that in an equilibrium state the electrons consist of two components, cold electrons and hot electrons with bi-Maxwellians. It is shown that low-frequency waves with right-hand polarization can be generated by the hot electron temperature anisotropy and the existence of cold electrons.

The propagation of small-amplitude hydromagnetic waves in a cold plasma mixed with hot ions is investigated using the first-order CGL equations for ions. It is assumed that in an equilibrium state the ions consist of two components, cold ions and hot ions with bi-Maxwellians. Propagation properties of hydro-magnetic waves are analysed by use of phase speed and refractive index surfaces, polarization and the amplitude ratio between perturbed density and magnetic field. It is shown that the existence of cold ions affects the properties of hydro-magnetic waves through finite frequency corrections only when the temperature anisotropy exists; and that the critical angle, at which the polarization sense changes from right-handed to left-handed as well as from left-handed to right-handed, can exist for intermediate and slow waves.