No abstract available

[en] Initiation and development of Pierce instability are possible in an electron beam passing between two electrodes, at maintaining the zero potential difference between tthem. Non-linear dynamics of electrons in the system is investigated with the use of numerical methods. It is shown that there exist soft and hard modes of exciting the Pierce instability. Stationary solutions, described analytically, are realized under soft mode. A virtual cathode, i.e. space where electron reflection takes place, is formed under hard mode of excitation in the system

[en] The effect of particle collisions in a plasma on the modulation instability is investigated. It is shown that in the case of the thermal modulation instability of a whistler, both excitation of other whistlers and lower-hybrid oscillations occur. The striction instability threshold is calculated, as well as increments and thresholds of the modulation instability of a whistler propagating along the magnetic field

[en] Nonlinear dynamics of the development of electromagnetic instability of low density electron monoenergetic beam, passing through a plasma, was investigated in hydrodynamic approximation. The corresponding system of equations is identical to the system of equations of nonlinear geometrical optics at k_c<<ω_p, and at k_c>>ω_p is similar to equations of charged particle motion, where similar charges are attracted, as opposed to the case of usual electrostatic interactions. It is shown, that development of electromagnetic instability rsults to sharp growth of electron density on beam axis. If beam electrons possess thermal velocity spread, stationary solutions are possible

[en] The nonlinear dynamics of development of an instability arising during electron beam passage between two electrodes with equal potentials is considered. The dependence of the value of mean current passing onto the anode in the mode with virtual cathode on the system parameters when ion shift is not substantial. Numerically investigated is the instability dynamics with account for ion motion. It is shown: 1) the dynamics of instability development in a short l< or approximately X, where X is potential hump and a long l>X systems is different which is connected with the possibility of formation in interelectrode interval of the long system of some virtual cathodes; 2) in the long system the explosion stage of electric field potential growth and accelerated ions attachment of anode with energies several times exceeding the beam electron energy

[en] The nonlinear stage of modulation instability of weakly ionized plasma is studied for long-wave perturbations kr₁ << 1 (k is the wave number, r₁ is the electron Larmor radius). The investigation is carried out in the one-dimensional model in which modulation of plasma density develops only in the direction normal to the magnetic field. The theoretical data well agree with the calculational ones. An analysis of numerical results shows that the development of thermal modulation instability in homogeneous magnetoactive plasma differs noticeably from the development of regular striction instability

[en] Stability of non-isotropic functions of distribution of ions with the empty ranges in the space of rates was studied. It was shown the in such a system the electrostatic waves might be excited. The increment and direction of wave vector of the excited oscillations were determined by parameters characterizing the empty range within ion phase space and by ratio of temperatures of electrons and ions. Quasilinear equation for waves propagating perpendicular to the current layer was solved and the energy of the excited oscillations was estimated depending on parameters of the ion hole

No abstract available

[en] Investigation into three-dimensional quasilinear equations describing the nonlinear evolution dynamics of ion-beam acoustic instability is conducted by numerical methods to explain the generation of the high-frequency spectrum part of wide-band electrostatic noise. It is shown that at first, quasilongitudinal electrostatic oscillations with frequencies, achieving the electron plasma frequency values and even higher, are more intensively excited, which corresponds to the experimentally observed spectrum. With the time flow the intensity maximum of the generated oscillations is shifted to the region of lower frequencies

[en] The Pierce instability can arise and develop as an electron beam is transported between two electrodes between which a zero potential difference is maintained. The nonlinear dynamics of the electrons in a system of this type has been studied numerically. The Pierce instability can manifest itself in ''soft'' and ''hard'' regimes. In the soft case, the relaxation toward steady-state solutions can be described analytically. In the hard case, a virtual cathode, a spatial region from which electrons are reflected, forms in the system