UKAEA Journals

Showing 1241 - 1250 of 1656 Journals Results
2008

A comparison is presented of measured and simulated parallel flows in the low field side scrape-off layer of MAST Ohmic shots. Simulations with B2SOLPS5.0 code reproduce the experimentally observed co-current rotation direction. The absolute values of the simulated Mach number are smaller than those of the measured ones; the difference might reach …

Published
2008

Measurements have been made of the emittance plot of a partly neutralized positive ion beamlet, using a slit, a polymer target, and an infrared camera. This thermographic approach is intrinsically linear and absolute since the properties of the target are known and approximately independent of temperature. It is sufficiently sensitive that only one…

Published
2008

Core localized Alfvén eigenmodes in DIII-D [J. L. Luxon, Nucl. Fusion 42 , 614 (2002)] and Joint European Torus JET [P. H. Rebut and B. E. Keen, Fusion Technol. 11 , 13 (1987)] plasmas are driven by deuterium neutral beam ions traveling well below the Alfvén speed. Modes are observed in reverse magnetic shear discharges with deuterium ion velocit…

Published
2008

In frequency modulated continuous wave reflectometry, used for density profile measurement in fusion plasmas, it is usual to measure the beat frequency between the launched wave and the reflected wave, and from this to calculate the position of the reflecting layer in the plasma. The absolute phase of the beat signal is usually neglected. The reaso…

Published
2008

Utilizing a capability to vary neutral beam torque injection in the DIII-D [J. L. Luxon, Nucl. Fusion 42 , 614 (2002)] tokamak, m / n =2/1 neoclassical tearing mode onset thresholds are found to fall by about one unit in βN , from 3 to 2, in ITER-like sawtoothing high-energy confinement modes of plasma operation [R. Aymar, Plasma Phys. Control. Fu…

Published
2008

Two approaches for studying the damping of resistive wall modes due to wave particle resonant interactions are discussed. One approach uses the eigenfunction from an ideal MHD code combined with the resonant particle damping calculated from a drift-kinetic Sf - method formulation. This perturbative approach treats the wave-particle interaction prec…

Published
2008

The tokamak plasma boundary, which is typically identified with the area of open field lines known as the scrape-off layer (SOL), determines the degree of plasmawall interaction. SOL physics, much of which is concerned with the exhaust (removal) of particles and energy from the plasma, has been one of the major topics investigated on JET during the…

Published
2008

In a fusion device such as a tokamak, it is well known that an unstable external kink mode, driven either by the plasma current or pressure, produces an external magnetic field perturbation, which induces stabilizing image currents in the surrounding conducting structures, such as the vacuum vessels made of low resistivity materials. The image curr…

Published