N. Ben Ayed K. G. McClements A. Thyagaraja
A perturbative three-dimensional analysis is presented of Alfvén waves in a magnetic X-point configuration with a strong longitudinal guide field. The waves are assumed to propagate in the direction of the X-line, and both the plasma beta and equilibrium plasma current are taken to be zero. This provides a simple model of Alfvén wave propagation …
PublishedA. Thyagaraja F. Schwander K. G. McClements
Collective fast ion effects on flows in tokamaks are investigated analytically and numerically. A general analysis of noncollisional electrodynamic momentum transfer from fast ions to bulk plasma is presented, with polarization effects and dissipation in the bulk plasma taken into account. The analysis is illustrated using idealized simulations of …
PublishedP. Mantica D. Van Eester X. Garbet F. Imbeaux L. Laborde M. Mantsinen A. Marinoni D. Mazon D. Moreau N. Hawkes E. Joffrin V. Kiptily S. Pinches A. Salmi S. Sharapov A. Thyagaraja I. Voitsekhovitch P. De Vries K.-D. Zastrow
The first electron temperature modulation experiments in plasmas characterized by strong and longlasting electron and ion internal transport barriers (ITB) have been performed in JET using ion cyclotron resonance heating in mode conversion scheme. The ITB is shown to be a well localized narrow layer with low heat diffusivity, characterized by subcr…
PublishedA. Thyagaraja K. G. McClements
Toroidal flow velocities of the order of the local sound speed and poloidal flows exceeding theoretical predictions have been observed in several tokamaks. Steady toroidal and poloidal flow effects are studied using dissipationless single-fluid and two-fluid theory, with electron inertia neglected in the latter case. An exact analytic treatment of …
PublishedK. G. McClements A. Thyagaraja
The injection of neutral particle beams counter to the plasma current direction in the Mega-Ampere Spherical Tokamak (MAST) [A. Sykes, R. J. Akers, L. C. Appel and et al. , Nucl. Fusion, 41 , 1423 (2001)] leads to substantial losses of energetic beam ions and also rapid toroidal rotation. The electrodynamic consequences of energetic ion loss on tok…
PublishedP. Mantica A. Thyagaraja J. Weiland G. M. D. Hogeweij P. J. Knight
Two fluid turbulence models, the drift wave based quasilinear 1.5D Weiland model and the electromagnetic global 3D nonlinear model CUTIE , have been used to account for heat pinch evidence in off-axis modulated electron cyclotron heating experiments in the Rijnhuizen Tokamak Project. Both models reproduce the main features indicating inward heat co…
PublishedM. R. De Baar A. Thyagaraja G. M. D. Hogeweij P. J. Knight E. Min
A two-fluid computer model of electromagnetic tokamak turbulence, CUTIE , is used to study the dynamic structure and turbulent transport in the Rijnhuizen Tokamak Project tokamak. A discharge with dominant, off-axis electron cyclotron heating is the main focus of the simulations which were extended over several resistive diffusion times. CUTIE repr…
PublishedC. N. Lashmore-Davies A. Thyagaraja D. R. Mccarthy
The mechanism of four nonlinearly interacting drift or Rossby waves is used as the basic process underlying the turbulent evolution of both the Charney-Hasegawa-Mima-equation CHME and its generalized modification GCHME. Hasegawa and Kodama’s concept of equivalent action or quanta is applied to the four-wave system and shown to control the distrib…
Published