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The paper is devoted to the first experimental study of distributed excitation of Görtler instability modes due the distributed mechanism of receptivity of a concave-wall boundary layer to streamwise freestream vortices. Experiments are carried out in the following range of problem parameters: Görtler numbers G* = 7,4÷21,3, frequencies f = 15, 20, and 26 Hz (nondimensional frequency parameters are F = 17,04; 22,72 and 29,54), and a broad range of spanwise scales of disturbances z = 8÷24 мм (nondimensional scales are Λ = 149÷774). It is found that this receptivity mechanism is quite efficient and can lead to amplification of unsteady Görtler vortices even in regimes where the boundary layer is linearly stable to these boundary-layer disturbances. Estimations of quantitative characteristics of the investigated physical phenomenon: the complex values of the distributed vortex receptivity coefficients are obtained in the present study for the first time. It is found that examined receptivity mechanism is especially effective for vortices with spanwise wavelengths close to the most dangerous in terms of the linear stability theory. The amplitudes of the receptivity coefficients are found to decrease with the streamwise coordinate

One of the effects of space charge is the charged particles current limitation in electron-optical systems. As a rule, for each specific system the limiting value of current can only be found on the results of numerical calculation, but the analytical treatment is necessary both for initial estimates of the parameters of the system and for understanding the physical basis of processes occurring in it. In this paper we consider a uniform circular beam of charged particles, partially filling a cylindrical vacuum chamber. The maximum perveance of this system depending on the ratio of pipe radius to beam radius is found, the comparison of this dependence with the results of numerical calculation of the system is carried out, as well as with the approximate analytical estimates

The technique of adiabatic invariant calculation in cross-section of magnetized intensive relativistic beam with consideration of drift motion of beam particles centers of rotation is suggested. Example of adiabatic invariant calculation of electrons of intensive beam in electrostatic accelerating system with longitudinal magnetic field is presented. It was shown that in strong enough magnetic field transverse energy of electrons preserves even at abrupt alteration of electric field.