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S. S. Elbakian

Publications and source records attributed to S. S. Elbakian.

5 recordsLinked to original sources

Excitation of nonlinear one-dimensional wake waves in underdense and overdense magnetized plasma by a relativistic electron bunch

The excitation of wake waves by a relativistic homogeneous electron bunch passing through cold magnetized plasma at equilibrium is studied for arbitrary values of the ratio of bunch density to plasma density. The analysis is based on the assumption that the magnetic field is sufficiently strong ($ω_B\gg ω_p$, where $ω_p$ and $ω_B$ are the electron plasma and cyclotron frequences respectively). The periodic and nonperiodic solutions for the momentum of plasma electrons inside and outside the bunch are analyzed. It was shown that the presence of strong external magnetic field may increase the amplitude of wake waves and the maximum transformer ratio, the latter being reached at densities of bunch lower than that in the absence of magnetic field. The optimum conditions for obtaining the maximum values of the wake field amplitude and of the transformer ratio are found.

physics.plasm-ph↗

Two-Dimensional Nonlinear Regime in the Plasma Wakefield Accelerator

The effect of nonlinearity on plasma wake wave excited by a relativistic cylindrical charged bunch is investigated. It is shown that owing to the nonlinearity the amplitude of wake wave gets modulated in the longitudinal direction. The nonlinear wavelength in the excited field changes in the transverse direction with the result that the phase front is distored and a turbulence developed. The nonlinear phase front distortion may be compensated by radial change of unperturbed plasma density.

physics.acc-ph↗

Excitation of Electromagnetic Wake Fields by one-dimensional Electron Bunch in Plasma in the Presence of Circularly Polarized Intense Electromagnetic Wave

The excitation of electromagnetic (EM) wake waves in electron plasma by an one-dimensional bunch of charged particles has been considered in the presence of intense monochromatic circularly polarized electromagnetic (CPEM) pump wave. In the zero state (in the absence of bunch) the interaction of the pump wave with plasma is described by means of Maxwell equations and relativistic nonlinear hydrodynamic equations of cold plasma. The excitation of linear waves by one-dimensional bunch is considered on this background. It is shown that there are three types of solutions of linear equations obtained for induced waves corresponding to three ranges of parameter values of the pump wave, bunch and plasma. In the first range of parameter values the amplitude of transverse components of induced waves is shown to grow as the bunch energy and after some value of the relativistic factor of the bunch to be almost independent of the energy and increase proportional to the intensity and frequency of the pump wave. The dependence of longitudinal component of induced waves on the relativistic factor of the bunch is weak. Its amplitude and wavelength grow as the intensity of pump wave. The second range of parameters is a resonance one. The amplitude of the wave excited by the bunch is a linear function of the distance to the bunch. In the third range of parameter values the longitudinal component of induced fields are localized near the bunch boundaries and are exponentially decreased with the increase in distance from these boundaries. The amplitudes of transverse components of induced waves reach a constant value with the distance from the bunch boundaries.

physics.plasm-ph↗

An Explicit Solution for Nonlinear Plasma Waves of Arbitrary Amplitude

Based on the known implicit solution for nonlinear plasma waves, an explicit solution was obtained in the form of decomposition into harmonics. The solution obtained exhibits a mechanism for steepening of nonlinear plasma wave as a result of increasing contribution of harmonics and may be used in theoretical studies of processes involving nonlinear plasma waves.

physics.plasm-ph↗

Three-dimensional wake fields, generated in plasma by cylindrical electron bunch

The expressions for wake fields, generated in plasma (in the plasma waveguide or unlimited plasma) by relativistic electron bunch, was received and analyzed for the cases of the presence and absence of strong external longitudinal magnetic field. For the both cases the comparative analysis of the dependence of field amplitudes on the parameters of the electron bunch was done.

physics.acc-ph↗