Showing papers by "Princeton Plasma Physics Laboratory published in 1981"
TL;DR: In this article, the authors studied the functional dependence of the coordinate q on the canonical angle variable θ in the complex θ-plane, where natural boundaries are found at constant absolute values of Im θ.
79 citations
TL;DR: In this paper, the stabilizing influence of finite-ion-gyroradius effects on magnetohydrodynamic ballooning modes for a simple model toroidal equilibrium is demonstrated.
Abstract: The stabilizing influence of finite-ion-gyroradius effects on magnetohydrodynamic ballooning modes for a simple model toroidal equilibrium is demonstrated
42 citations
TL;DR: In this paper, a horizontal polarization from the outside midplane at an angle nearly perpendicular to the 10-kG toroidal field of the JFT-2 tokamak was reported.
Abstract: Radio-frequency power of up to 110 kW for 14 ms at 28 GHz is launched in a horizontal polarization from the outside midplane at an angle nearly perpendicular to the 10-kG toroidal field of the JFT-2 tokamak. With initial Ohmic power comparable to the RF power, the central electron temperature increases from 600 to 1000 eV in 10 ms. Details of the electron heating are reported.
38 citations
TL;DR: In this article, the ballooning-mode formalism was employed to reduce the two-dimensional eigenmode equation for trapped-electron instabilities in tokamaks to a one-dimensional integro-differential equation along the magnetic field lines and then analyzed both analytically and numerically.
Abstract: Employing the ballooning-mode formalism, the two-dimensional eigenmode equation for trapped-electron instabilities in tokamaks is reduced to a one-dimensional integro-differential equation along the magnetic field lines and then analysed both analytically and numerically. Dominant toroidal coupling effects are due to ion magnetic drifts which create quasi-bound states. The trapped-electron response can be treated as a perturbation and is found to de-stabilize the quasi-bound states.
31 citations
TL;DR: In this article, the effect of impurities on thermally unstable plasmas was considered and their effect on current diffusion into regions of high conductivity was investigated. But the effect on impurities was not discussed.
Abstract: A plasma can become thermally unstable because of the temperature dependence of the heating and cooling functions. Such an instability can occur as a consequence of current diffusion into regions of high conductivity. The effect of impurities on this instability is considered.
3 citations
01 Jan 1981
TL;DR: In this article, the authors used a bremsatrahlung and recombination continuum and characteristic line spectra of impurity ions from the plasma limiter and the walls of the vacuum vessel.
Abstract: Tokamak discharges, which are studied for the magnetic confinement of fusion plasmas, emit soft x-ray radiation in the energy range from 1–20 keV. This radiation consists of a bremsatrahlung and recombination continuum, and characteristic line spectra of impurity ions from the plasma limiter and the walls of the vacuum vessel. The radiation represents a unique source of information and is increasingly used as a diagnostic of plasma parameters. This includes measurements of the electron and ion temperature, investigation of the ionization equilibrium and particle transport, and the study of MHD fluctuations and disruptions.
2 citations
TL;DR: In this article, the authors present an overview of the analysis and data of the past ten years, including the classical analysis, the Culham effect, and the PLT effect, which suggests wall outgassing is a significant gas source.
Abstract: Reionization losses in neutral beams for magnetic confinement devices are significant and thus they are an important design consideration. This paper presents an overview of the analyses and data of the past ten years. Included is the traditional analysis, or Classical Effect, which considers the ion source and neutralizer as gas sources; the Culham Effect, which considers gas molecules knocked from walls as a significant additional gas source; and the PLT effect, which suggests wall outgassing is a significant additional gas source.
2 citations
TL;DR: This expression is used by land surveyors for at least a century, is easily remembered, and is surprisingly accurate: for d = ft/4, the error is less than one part in 2000.
Abstract: will be found to be quite satisfactory. It has been used by land surveyors for at least a century, can be easily remembered, and is surprisingly accurate: for d = ft/4, the error is less than one part in 2000. In addition to the recommended use in setting lenses, this expression is also convenient in determining the departure from plane of a Gaussian beam of a given radius of curvature over a specified aperture.
2 citations
TL;DR: An intensive, year-long, international evaluation of the next major tokamak beyond the generation of large experiments currently under construction was carried out during 1979 as discussed by the authors, which consisted of the definition of objectives, an assessment of the physics and technology base and R and D needs and the identification of a set of parameters that physically characterize the machine.
1 citations
TL;DR: In this paper, it was suggested that the blanket may not be changed for the plant lifetime, and miniaturization of OCLATOR is discussed, especially if the ripple turbulence could be improved upon the presently set limit which applies to a large number of ripples.
Abstract: Following the general description of OCLATOR (I), more thoughts are presented here. It suggests that the blanket may not be changed for the plant lifetime. Also miniaturization of OCLATOR is discussed, especially if the ripple turbulence could be improved upon the presently set limit which applies to a large number of ripples.