[en] A survey is given of the main problems of high-temperature plasma physics. The knowledge is summed up on reserves of fissionable materials and raw materials for nuclear fusion, methods of plasma confinement and heating. The basic theoretical considerations are presented on plasma behaviour, the current state of theory and experiment and prospects of future development. (Z.S.)

[en] The effect of stochastic instability of particle motion on nonlinear Landau damping was investigated on a simple model of particles with a discrete spectrum. It was shown that as far as the trajectory of particles was stochastically unstable (at beat resonances under consideration), diffusion of particles took place. The influence of this effect on the nonlinear Landau mechanism commonly assumed is discussed; the possibility of heating in this regime in a beam-plasma experiment is dealt with briefly. (author)

[en] The interaction of RF field with toroidally trapped particles (bananas) can cause their intrinsic stochastically diffusion both in the configuration and velocity space. In RF heating and/or current drive regimes, RF field can interact with plasma particles and with thermonuclear alpha particles. The aim of this contribution is to give some analytical estimates of induced radial diffusion of alphas and of ions. (author)

[en] The interaction of two interfering monochromatic waves with particles having the velocity close to that of the wave beat is studied. The particles can be trapped in the effective beat potential trough. Expressions for the frequency of their oscillations and a canonically conjugated coordinate and momentum are derived. The backward effect of the trapped particles on the wave modulation is expressed in perturbation of the effective potential. The changed beat potential results in multiperiodicity of motion of particles, their phase bunching, and in instability in the second Mathieu region. The latter phenomenon suo-gests the possibility of energy transfer to particles via modulation of both waves at the second harmonic of the trapped-particle oscillations. (J.U.)

No abstract available

[en] The motion of particles in a finite amplitude wave propagating obliquely to a homogeneous magnetostatic field is discussed. It follows from simple integral properties that in the neighbourhood of Doppler-shifted cyclotron resonance similar trapping effects appear as in a plasma without magnetostatic field. The consequences of this trapping are discussed, in particular the possibility of a strong absorption of the wave and the origin of stochastic instabilities, caused by the perturbation of an effective trapping potential and leading to particle acceleration. (author)

[en] Basic equations and numerical results describing nonlinear interaction of a weakly modulated electron beam with a single stationary one-dimensional wave excited in a cold plasma without the magnetic field, are presented and discussed. The effect of all possible irreversible processes (e.g., plasma turbulence) accompanying this interaction is simulated by the constant effective collision frequency νsub(eff) of plasma electrons. Starting from the nonlinear Poisson equation, the expression for the amplitude and the phase of the beam-excited wave are derived and solved numerically together with the equations of the beam electron motion. The results are compared with those of a time model. Significant, experimentally detectable differences are established. (author)

No abstract available

[en] The interaction in a cold electron beam-plasma system is investigated numerically in a density ratio region of nsub(B)/nsub(P) = 2 x 10^-3 to 2 x 10^-2. The one-dimensional model of a collisionless plasma is used. The time development of the wave with maximal growing rate and its spatial harmonics is studied. The plasma effect is simulated by direct computation of plasma particle trajectories (this being different from the usual plasma simulation by means of a dielectric). The calculations show the following effects of the finite parameter (nsub(B)/nsub(P))sup(1/3): the ratio of the plasma energy to the electric field energy is increased, the damping character of the field and macroscopic amplitudes reveals, and the influence of the second harmonic is not negligible for nsub(B)/nsub(P) >= 10^-2. (author)

[en] Monochromatic Alfven wave interaction with toroidaly trapped particles in the intrinsic stochasticity regime is discussed. Both the diffusion in velocities and in the radial position of bananas is studied. Using a suitable Hamiltonian formalism, the effect of wave parallel components E-tilde_paral and B-tilde_paral is investigated. The stochasticity threshold is estimated for plasma electrons and for thermonuclear alpha-particles (neglecting the effect of B-tilde_paral) by means of direct numerical integration of the corresponding canonical equations. Stochasticity causes transfer between trapped and untrapped regimes and the induced radial diffusion of bananas. The latter effect can considerably exceed neoclassical diffusion. The effect of B-tilde_paral was only estimated analytically. It consisted in frequency modulation of the banana periodic motion coupled with a possible Mathieu instability. Nevertheless, for B-tilde_paral corresponding to E-tilde_paral, the effect seems to be weaker than the effect of E-tilde_paral when the thermonuclear regime is considered. (author). 14 figs., 36 refs