#### C. N. Lashmore-Davies V. Fuchs A. K. Ram A. Bers

An analysis of ion cyclotron resonance heating in a plasma containing two ion species is given. Particular emphasis is placed on the important case of comparable concentrations of the two species. The properties of ion-Bernstein waves in such a plasma are discussed. A summary of the cutoff– resonance (Budden) and cutoff–resonance–cutoff (trip…

Published#### C D Warrick B Lloyd M R O’Brien

Electron cyclotron (EC) waves can perform a variety of roles in ITER including start-up assist, heating to ignition, on and off-axis current drive and instability control. EC wave absorption is robust and well understood producing highly localised heating with total absorption anticipated for almost all parameters foreseen in ITER. Other advantages…

Published#### R. D. Hazeltine P. Helander Peter J. Catto

The simplest nontrivial model of transport across a magnetic island chain in the presence of collisionless streaming along the magnetic field is solved by a Wiener–Hopf procedure. The solution found is valid provided the boundary layer about the island separatrix is narrow compared to the island width. The result demonstrates that when this assum…

Published#### R. A. Cairns V. Fuchs C. N. Lashmore-Davies

We apply a fast wave approximation to the propagation of the fast wave across the magnetic field. This approximation involves replacing the hot plasma conductivity tensor by an approximation which reduces the problem to a second order differential equation. Such a procedure is particularly useful in the high harmonic regime, where many terms with t…

Published#### Colin George Windsor Thomas Noel Todd David Leonard Trotman Michael Edward Underhill Smith

The plasma position and shape on the COMPASS-D tokamak have been controlled simultaneously with a 75- kHz bandwidth, hard-wired, real-time neural network. The primary network operates with up to 48 selected magnetic inputs and has been used in the vertical position control loop to control the position of the upper edge of the plasma at the radius o…

Published#### P. Helander R. J. Hastie J. W. Connor

The bootstrap current in a non-Maxwellian tokamak plasma with electron cyclotron heating is calculated. The calculation is exact in the limit of highly charged ions, where pitch-angle scattering dominates over quasilinear diffusion, and shows that the current is entirely determined by the pressure of the trapped electrons. If the ion charge is fini…

Published#### D. C. Mcdonald R. A. Cairns C. N. Lashmore-Davies

Electron cyclotron absorption (ECA) of electromagnetic radiation at the second harmonic is of interest in Tokamak physics both for plasma heating and current drive, as well as for some diagnostics. Modelling of the linear wave propagation for such problems is usually done by WKB ray tracing, despite the fact that the WKB theory is not strictly vali…

Published#### C. N. Lashmore-Davies A. Thyagaraja R. A. Cairns

A cylindrical model of a tokamak is used to describe the nonlinear coupling between Alfven waves and sound waves. The model is applied to the case of a toroidal Alfven eigenmode (TAE) driven unstable by fusion alpha particles to explore its relevance to the nonlinear saturation of such modes, which can produce a loss of alpha particles in a burning…

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