T. Onjun A. H. Kritz G. Bateman V. Parail
Studies of type 1 ELMy H-mode pedestals are carried out using 0 D and 1.5 D approaches. In the 0 D study, predicted pedestal temperatures are compared with 533 data points. The pedestal temperature models, with pedestal width based on magnetic and flow shear stabilization and neutral penetration, yield an RMSE of 32% and 53.4%, respectively, when c…
PublishedR. G. L. Vann R. O. Dendy G. Rowlands T. D. Arber N. D’Ambrumenil
The Berk–Breizman augmentation of the Vlasov–Maxwell system is widely used to model self-consistent resonant excitation and damping of wave fields by evolving energetic particle populations in magnetic fusion plasmas. The key model parameters are the particle annihilation rate, which drives bump-on-tail structure, and the linear wave damping ra…
PublishedM. J. Hole R. S. Dallaqua S. W. Simpson E. Del Bosco
Ever since conception of the Vacuum Arc Centrifuge (VAC) in 1980, periodic fluctuations in the ion saturation current and floating potential have been observed in Langmuir probe measurements in the rotation region of a VAC. Our theoretical and experimental research suggests that these fluctuations are in fact a pressure-gradient driven drift mode. …
PublishedM. 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…
PublishedA. Ekedahl L. Colas M.L. Mayoral B. Beaumont Ph. Bibet et al.
Combined operation of Lower Hybrid (LH) and Ion Cyclotron Resonance Frequency (ICRF) waves can result in a degradation of the LH wave coupling, as observed both in the Tore Supra and JET tokamaks. The reflection coefficient on the part of the LH launcher magnetically connected to the powered ICRF antenna increases, suggesting a local decrease in th…
PublishedR. Barnsley N. J. Peacock J. Dunn I. M. Melnick I. H. Coffey et al.
A family of Johann configuration curved crystal spectrometers has been designed to share the basic engineering features of compactness, modularity, facility of alignment and focus, and incorporation of solid-state charge coupled device detector arrays. These detectors have intrinsically low noise, useful energy resolution, two-dimensional position …
PublishedD.B. King V.M. Nakariakov E.E. Deluca L. Golub K.G. McClements
Quasi-periodic EUV disturbances simultaneously observed in 171 Å and 195 Å TRACE bandpasses propagating outwardly in a fan-like magnetic structure of a coronal active region are analysed. Time series of disturbances observed in the different bandpasses have a relatively high correlation coefficient (up to about 0.7). The correlation has a tendenc…
Published