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1997
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…
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1997
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…
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1997
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…
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1997
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…
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1997
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…
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1996
The stability of the ion hybrid wave in a plasma containing two thermal ion species present in comparable proportions and a low density population of superthermal alpha-particles is analyzed. A simple, model distribution function consisting of a ring distribution in the perpendicular velocity and a Maxwellian in the parallel velocity is used for th…
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1996
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1996
The diffusion of test particles in a turbulent electrostatic field is investigated numerically. The field is obtained by solving the Hasegawa–Mima model for two-dimensional drift turbulence. It is shown that nonlinear coupling significantly reduces the level of transport compared to the linear regime, and the physical mechanisms leading to this e…
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1996
This paper reports on the ideal magnetohydrodynamic (MHD) stability of tokamak field profiles that have a non-monotonic safety factor q ( r ). An analytic criterion is obtained for these ‘‘inverse shear’’ profiles by expanding in inverse aspect ratio and assuming that the minimum in q is slightly less than the m / n value of the mode under …
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1996
Advanced Tokamak Concepts [C. Kessel, J. Manickam, G. Rewoldt, and W. M. Tang, Phys. Rev. Lett. 72 , 1212 (1994)] have been designed assuming that the ‘‘Resistive Wall Mode’’ (RWM) is stable. It has recently been shown that the RWM can be stabilized by a combination of strong uniform plasma rotation and visco-resistive dissipation. In this …
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