[en] Equations have been derived which describe the nonlinear behaviour of drift waves in the framework of weak turbulence theory. The nonlinear terms arise from (nonlinear) electric and diamagmetic drifts. The turbulence level and the diffusion coefficient are estimated, and good agreement is found with experimental results

No abstract available

No abstract available

[en] The drift waves related to the magnetic plasma confinement are observed in confinement devices. A number of mechanisms are theoretically shown to be able to render them instable. ODE experiments devoted to the study of their behavior in connection with a specific stabilizing mechanism (collisionnal wave, resonant wave and partly trapped electron wave) shown a strong agreement between observations and theoretical predictions in the laminar range

[en] An experiment on the transition to turbulence in a plasma with a limited number of discrete modes of the collisionless drift instability is analysed in terms of the present-day picture of intrinsic stochasticity. The modes are described as an ensemble of weakly coupled van der Pol oscillators which are initially synchronized but lose synchronization because of finite Larmor radius effects and length effects, which cause detuning

No abstract available

No abstract available

[en] A theory of the anomalous transport in Tokamak is reviewed. For the comparison, the neo-classical theory is briefly presented. Taking the view point that the drift wave turbulence may explain the observed anomaly of the electron heat transport, we show how the drift wave occurs and present a brief exposure of the nonlinear theory necessary for the computation of the anomalous transport coefficients. (Author)

[en] In plasma physics, linear instability calculations can be implemented either as initial value calculations or as eigenvalue calculations. Here, comparisons between comprehensive linear gyrokinetic calculations employing the ballooning formalism for high-n (toroidal mode number) toroidal instabilities are described. One code implements an initial value calculation on a grid using a Lorentz collision operator and the other implements an eigenvalue calculation with basis functions using a Krook collision operator. An electrostatic test case with artificial parameters for the toroidal drift mode destabilized by the combined effects of trapped particles and an ion temperature gradient has been carefully analyzed both in the collisionless limit and with varying collisionality. Good agreement is found. Results from applied studies using parameters from the Tokamak Fusion Test Reactor (TFTR) experiment are also compared

[en] The local quasiclassical theory of the drift-dissipative instability is in good agreement with the experimental data but it cannot explain some detected peculiarities of the phenomenon, namely the radial wave structure and the absence of the m=1 oscillations. It is shown that these discrepancies can be explained substituting the local quasiclassical approximation theory by a hydrodynamical theory. Solving the differential equations by taking into account the cylindrical walls limiting the plasma, the experimental results can be reproduced. The plasma limits play an important role in the drift-dissipative instability. (D.Gy.)