UKAEA Papers

"Combined visible and infrared Thomson scattering on the MAST experiment"

• M. J. Walsh
• E. R. Arends
• P. G. Carolan
• M. R. Dunstan
• M. J. Forrest
• et al.

A dual laser Thomson scattering system is implemented in the Mega Amp Spherical Tokamak (MAST). The complementary features of each approach are exploited. One system is ideally suited to measuring detailed profile behavior across the plasma while the other is ideally suited though not exclusively to studying fast changing events and general charact…

"L-H Transition in the Mega-Amp Spherical Tokamak"

• R. J. Akers
• G. F. Counsell
• A. Sykes
• L. C. Appel
• E. R. Arends
• C. Byrom
• P. G. Carolan
• N. J. Conway
• G. Cunningham
• A. Dnestrovskij
• Yu.N. Dnestrovskij
• A. R. Field
• S. J. Fielding
• M. Gryaznevich
• P. Helander
• A. Kirk
• S. Korsholm
• R. Martin
• H. Meye

H -mode plasmas have been achieved on the MAST spherical tokamak at input power considerably higher than predicted by conventional threshold scalings. Following L - H transition, a clear improvement in energy confinement is obtained, exceeding recent international scalings even at densities approaching the Greenwald density limit. Transition is acc…

"Damping of relativistic electron beams by synchrotron radiation"

• F. Andersson
• P. Helander
• L.-G. Eriksson

Relativistic electrons emit synchrotron radiation due to their gyro- and guiding-center motions in a curved magnetic field. In this article, the kinetic theory of relativistic electron beams is developed to account for radiation reaction by including the Abraham–Lorentz reaction force in the kinetic equation. As an application of this theory, the…

"Interactive optical design and realization of an optimized charge coupled device Thomson scattering system for the spherical tokamak START"

• M. J. Walsh
• N. J. Conway
• M. Dunstan
• M. J. Forrest
• R. B. Huxford

"Ideal magnetohydrodynamic stability of the tokamak high-confinementmode edge region"

• H. R. Wilson
• J. W. Connor
• A. R. Field
• S. J. Fielding
• R. L. Miller
• et al.

The ideal magnetohydrodynamic (MHD) stability of the tokamak edge is analyzed, with particular emphasis on radially localized instabilities; it is proposed that these are responsible for edge pressure gradient limits and edge localized modes (ELMS). Data and stability calculations from DIII-D [to appear in Proceedings of the 16th International Conf…

"Two novel applications of bootstrap currents: Snakes and jitter stabilization"

• A. Thyagaraja
• F. A. Haas

Both neoclassical theory and certain turbulence theories of particle transport in tokamaks predict the existence of bootstrap (i.e., pressure-driven) currents. Two new applications of this form of noninductive current are considered in this work. In the first, an earlier model of the nonlinearly saturated m= 1 tearing mode is extended to include th…

"Improved signaltonoise in fluorescence scattering by means of nonlinear pumping with a frequency modulated dye laser"

• M. J. Forrest
• R. J. Winfield

Laser-induced fluorescence (LIF) is a well established technique used to determine the neutral hydrogen density in fusion plasmas.There is a requirement to extend these measurements to the Divertor section of large plasma devices, but this is problematical due to the high levels of stray laser light and background plasma emission. Here we describe …