G. V. Pereverzev

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This contribution presents theoretical results on the transport of light and heavy impurities, as well as of energetic α particles, produced by the background electrostatic plasma turbulence. Linear and nonlinear simulations with three gyrokinetic codes, GS2, GYRO, and the recently developed GKW, are performed in concert with analytical derivations, in(More)
Use of a large-area liquid lithium limiter in the CDX-U tokamak produced the largest relative increase (an enhancement factor of 5-10) in Ohmic tokamak confinement ever observed. Numerical simulations of CDX-U low recycling discharges have now been performed with the ASTRA code, utilizing a model with neoclassical ion transport and boundary conditions(More)
Energy transport by the electrons in a tokamak is examined in steady-state and power modulation experiments using electron cyclotron heating. The results are consistent with the assumption that temperature profiles are limited by a critical gradient length, leading to "stiff" profiles. The modulation experiments show that the stiffness factor increases with(More)
It is known that the anomalous transport in fusion devices is governed by gradient-driven instabilities and is characterised by an offset linear dependence of the heat and particle fluxes on the corresponding gradients. The dependence is very strong so that a small increase in gradients causes a huge enhancement of fluxes thus giving rise to the so called(More)
Accurate simulations of Neutral Beam Injection (NBI) in tokamak plasmas are vitally important for the analysis of present experiments since NBI is a main heating and current drive tool used in many tokamaks. Different numerical techniques including Monte-Carlo (MC) simulations of beam particles and the solution of the Fokker-Planck (FP) equation for the(More)
In the ASDEX Upgrade tokamak, high poloidal beta up to beta(pol) = 3 at the Greenwald density with H-mode confinement has been reached. Because of the high beta, the plasma current is driven almost fully noninductively, consisting of 51% bootstrap and 43% neutral beam driven current. To reach these conditions the discharge is operated at low plasma current(More)
The existence of an anomalous particle pinch in magnetized tokamak plasmas is still questioned. Contradictory observations have been collected so far in tokamaks. Clear experimental evidence that density peaking in tokamak plasmas drops with increasing collisionality is provided for the first time. This phenomenon is explained by means of existing(More)
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