J. W. Connor R. J. Hastie
It has been suggested [Kleva and Guzdar, Phys. Plasmas 6 , 116 (1999)] that reconnecting ballooning modes in which electron inertia replaces resistivity in a nonideal magnetohydrodynamic Ohm’s law can have substantial growth rates in the low collisionality regime. Numerical calculation, albeit necessarily at unrealistically large values of the co…
PublishedA. Bondeson C. G. Gimblett R. J. Hastie
The possibility of stabilizing ideal magnetohydrodynamical (MHD) instabilities by resistive walls and slow plasma rotation (rotation frequencies comparable to resistive tearing growth rates) was proposed recently by Finn [Phys. Plasmas 2 , 3782 (1995)] on the basis of cylindrical theory. In the present paper we analyze toroidal effects (pressure gr…
PublishedH. R. Wilson R. L. Miller
The peeling mode restricts access to the second stability region of the ideal ballooning mode at the tokamak plasma edge. Using a two-dimensional, high toroidal mode number eigenmode code employing a model tokamak equilibrium, it is shown that a window to second stability exists for a sufficiently deep magnetic well. The different mode structures o…
PublishedY. Nagayama K. Kawahata A. England Y. Ito N. Bretz et al.
The electron cyclotron emission ~ECE! diagnostic system is installed on the large helical device ~LHD!. The system includes the following instruments: a heterodyne radiometer, a Michelson spectrometer, and a grating polychromator. A 63.5 mm corrugated waveguide system is fully utilized. Large collection optics and notch filters at the frequency of …
PublishedN. J. Peacock K. D. Lawson R. Barnsley H. Chen
An empirical procedure, ‘‘LINT,’’ for relating emission line intensities of intrinsic impurity ions to their elemental contributions to the total, bolometric, radiation loss and the volume-averaged effective ion charge, Zeff , has been developed and applied to limiter plasmas in the JET tokamak. In this article we discuss extensions to the …
PublishedA. J. H. Donné T. Edlington E. Joffrin H. R. Koslowski C. Nieswand et al.
The polarimeter system for ITER features 10 viewing chords covering almost the full poloidal cross section of the plasma in a fan-like arrangement. The 10 laser beams all enter the plasma via 150 mm diam penetrations through the diagnostic plug at the low-field side. Small retroreflectors at the high-field side mirror the laser beams back towards t…
PublishedA. Thyagaraja
This paper and a forthcoming one develop the spectral theory of ballooning transformations relevant to tokamak physics from rst principles in a rigorous and yet intuitively clear manner. The power of the ballooning representation to throw light on the spectral characteristics of the plasma problems to which it is applicable is emphasized, and examp…
PublishedParag Vyas Denis Mustafa A. William Morris
Theoretical and experimental work on the vertical position control system on the COMPASS-D tokamak is described. An analog proportional 1 derivative (P 1 D) system is currently used, and two important sources of disturbance are observed in the system. One source is 600-Hz noise from thyristor power supplies, and the other is impulselike disturbance…
PublishedP. Helander
In a toroidally rotating tokamak plasma, heavy impurity ions accumulate on the outside of each flux surface under the action of the centrifugal force. The collision frequency therefore varies over the flux surface. This circumstance is shown to enhance the neoclassical transport processes, including the bootstrap current, by making collisions occur…
Published