
2007

2005
The mechanism of four nonlinearly interacting drift or Rossby waves is used as the basic process underlying the turbulent evolution of both the CharneyHasegawaMimaequation CHME and its generalized modification GCHME. Hasegawa and Kodama’s concept of equivalent action or quanta is applied to the fourwave system and shown to control the distrib…

2004
The generalized CharneyHasegawaMima equation is unstable to a four wave modulational instability whereby a coherent, monochromatic drift wave can drive a band of modes and associated zonal flows unstable. Although initially the fastest growing modes dominate, a secondary nonlinear instability later drives the longest wavelength zonal flow and its…

2002
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, PetitLancy, 1998), Vol. 22A…

2001
The linear and nonlinear dynamics of zonal flows and their interactions with drift wave turbulence is considered in the simple but illuminating generalized Charney–Hasegawa–Mima model due to Smolyakov et al. [Phys. Plasmas 7 , 1349 (2000)]. Two positive definite, exact, integral invariants associated with the full generalized Charney–Hasegawa…

2001
A cylindrical model with an equilibrium surface current and a uniform equilibrium plasma flow velocity parallel to the axis of the cylinder is used to investigate resistive wall instability. This system can be unstable to the ideal, external kink mode, which can be stabilized by the presence of a perfectly conducting wall. This is the classic condi…

2001
An approximation to the relativistic broadening of an electron cyclotron resonance is obtained by including only the effect of the momentum parallel to the magnetic field. This approximation is then applied to the calculation of the absorption of the electromagnetic Xmode and compared to the full relativistic analysis with which it agrees very wel…

2000
Electron Bernstein waves are analyzed as possible candidates for heating spherical tokamaks. An inhomogeneous plane slab model of the plasma with a sheared magnetic field is used to calculate the linear conversion of the ordinary mode (Omode) to the extraordinary mode (Xmode). A formula for the fraction of the incident Omode energy which is conv…

1999
A uniform compressible plasma with a uniform flow along the magnetic field in the presence of a resistive wall is shown to be subject to two instabilities. For the first instability, the flow velocity is required to exceed the Alfve´n speed, whereas for the second it need only exceed the sound speed. For a sufficiently high ion temperature, ion La…

1999
Showing 1  10 of 21 UKAEA Paper Results