S. Shiraiwa S. Ide S. Itoh O. Mitarai O. Naito T. Ozeki Y. Sakamoto T. Suzuki Y. Takase S. Tanaka T. Taniguchi M. Aramasu T. Fujita T. Fukuda X. Gao M. Gryaznevich K. Hanada E. Jotaki Y. Kamada T. Maekawa Y. Miura K. Nakamura T. Nish
A new operational scenario of advanced tokamak formation was demonstrated in the JT-60U tokamak. This was accomplished by electron cyclotron and lower hybrid waves, neutral beam injection, and the loop voltage supplied by the vertical field and shaping coils. The Ohmic heating (OH) solenoid was not used but a small inboard coil (part of the shaping…
PublishedA.J. Webster H.R. Wilson A.M.M. Scaife
A tokamak’s economic performance is strongly affected by the plasma pressure that it may sustain, which in turn is limited by the maximum pressure gradients that may be supported. Ballooning modes are typically driven unstable by increasing the pressure gradient, and because they can radially extend across many rational surfaces, they can serious…
PublishedT.K. March S.C. Chapman R.O. Dendy J. A. Merrifield
Previous observations that suggest a substantial role for nondiffusive energy transport in tokamaks subjected to off-axis electron cyclotron heating (ECH) are compared to the output from a sandpile model. The observations considered include local and global aspects of temperature profile evolution in the DIII-D [for example, C. C. Petty and T. C. L…
PublishedR. E. Lee S. C. Chapman R. O. Dendy
The identification of preacceleration mechanisms for cosmic ray ions in supernova remnant shocks is an important problem in astrophysics. Recent particle-in-cell ( PIC ) shock simulations have shown that inclusion of the full electron kinetics yields non-time-stationary solutions, in contrast to previous hybrid ( kinetic ions, fluid electrons ) sim…
PublishedN. J. Sircombe T. D. Arber R. O. Dendy
Direct numerical simulations of electron dynamics in externally driven electrostatic waves have been carried out using a relativistic two-fluid one-dimensional Vlasov–Poisson code. When the driver wave has sufficiently large amplitude, ion density holes ( cavitons ) form. The interaction between these cavitons and other incoming Langmuir waves gi…
PublishedK.J.H. Phillips J.A. Rainnie L. K. Harra J. Dubau F.P. Keenan N.J. Peacock
The inclusion of collisional rates for He-like Fe and Ca ions is discussed with reference to the analysis of solar flare Fe XXV and Ca XIX line emission, particularly from the Yohkoh Bragg Crystal Spectrometer (BCS). The new data are a slight improvement on calculations presently used in the BCS analysis software in that the discrepancy in the Fe X…
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 …
PublishedJ. B. Taylor
Ripples in the confining field may exert a torque on a rotating plasma. Time reversal symmetry implies that this torque should vanish for an ideal plasma. However, even in an apparently ideal plasma, singularities can give rise to a nonzero torque. This torque is evaluated for a simple configuration. Although the primary force is magnetic, an essen…
PublishedR. 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…
PublishedA. K. Ram A. Bers C. N. Lashmore-Davies
In previous publications [A. K. Ram and S. D. Schultz, Phys. Plasmas 7 , 4084 (2000) ; A. Bers, A. K. Ram, and S. D. Schultz, in Proceedings of the Second Europhysics Topical Conference on RF Heating and Current Drive of Fusion Devices , edited by J. Jacquinot, G. Van Oost, and R. R. Weynants (European Physical Society, Petit-Lancy, 1998), Vol. 22A…
Published