V.A. Balakirev

Charged particle acceleration by an intense wake-field excited in plasmas by either laser pulse or relativistic electron bunch

The results from theoretical and experimental studies, as well as from 2.5-dimensional (2.5-D) numerical simulation of plasma wake field excitation, by either relativistic electron bunch, laser pulse, and the charged particle wake field acceleration are discussed. The results of these investigations make it possible to evaluate the potentialities of the wake field acceleration method and to analyze whether it can serve as a basis for creating a new generation of devices capable of charged particle accelerating at substantially higher (on the order of two to three magnitudes) rates in comparison with those achievable in classical linear high-frequency (resonant) accelerators.

Charged prticle aceleration by an itense ultrashort electromagnetic pulse excited in a plasma by laser radiation or by relativistic electron bunches

A review is given of theoretical and experimental investigations and numerical simulations of the generation of intense electromagnetic fields in accelerators based on collective methods of charged particle acceleration at rates two or three orders of magnitude higher than those in classical resonance accelerators. The conditions are studied under which the excitation of accelerating fields by relativistic electron bunches or intense laser radiation in a plasma is most efficient. Such factors as parametric and modulational processes, the generation of a quasistatic magnetic field, and the acceleration of plasma electrons and ions are investigated in order to determine the optimum conditions for the most efficient acceleration of the driven charged-particle bunches.

Broadband emission from a relativistic electron bunch in a semi-infinite waveguide

A study is made of the excitation of a transition radiation pulse during the injection of a charged particle bunch through the end metal wall into a semi-infinite cylindrical waveguide. Exact analytic expressions for the fields of a thin ring-shaped bunch are obtained in terms of the Lommel functions of two variables. The energy efficiency, power, and spectrum of radiation emitted from a finite-size charged bunch in a vacuum waveguide are calculated numerically with allowance for the multimode nature of the excited field. It is shown that, under certain conditions, the bunch can generate a short, high-intensity electromagnetic pulse with a broad frequency spectrum. The effect of various parameters of the charged bunch-waveguide system (such as the bunch current, bunch duration, and waveguide radius) on the generation efficiency of a transition radiation pulse is investigated.

Removal of asphalt-paraffin deposits in oil pipelines by a moving source of high-frequency electromagnetic radiation

A new method for removing asphalt-paraffin and gasohydrate plugs in oil pipelines with a movable source of electromagnetic radiation, electromagnetic pig, is suggested. The pig melts the plug when the latter absorbs intense electromagnetic radiation and heats up. Effective melting of the dielectric plug is achieved with the source moving along the pipeline as the solid-liquid interface propagates. The time of paraffin plug removal and the dependence of this time on the radiation frequency are found with the model suggested. The efficiency of the method is estimated.

Generation of UHF oscillations in slowing down lines with magnetic insulation

In leading laboratories of the world intensive research on powerful microwave generators with magnetic self-isolation (MILO) is being carried out. In the present work the results of calculation and theoretical analysis of MILO, designed and tested in the Institute of Electromagnetic Research (IEMR), are given.

Excitation of Langmuir Oscillations by a Laser Pulse in a Semi-Infinite Dense Plasma

A study is made of the nonlinear mechanism for the excitation of Langmuir waves in a dense plasma by an intense laser pulse with the frequency ω = ωp/2 (where ωp is the electron plasma frequency).

Charged particles accelerated by wake fields in a dielectric resonator with exciting electron bunch channel

We have studied the acceleration of electrons by wake fields excited in a resonator by a train of electron bunches. The resonator comprised a cylindrical metal waveguide section, containing a dielectric sleeve with a vacuum channel and ends closed by metal walls. Expressions describing the wake field excited by uniformly moving exciting electron bunches have been derived. The self-consistent process of resonator excitation by a train of charged bunches and the particle acceleration in the excited wake field has been numerically simulated.

Theory of microwave amplification in a coaxial ubitron

Results are presented from a theoretical study of the microwave amplification process in a coaxial ubitron with an undulator based on permanent annular magnets. Such an undulator is used for both focusing of a high-current relativistic electron beam (REB) and excitation of microwave radiation. The spatial structure of the magnetic field in a coaxial undulator is obtained. It is shown that optimum transport of the REB is possible under certain conditions for the parameters of the coaxial undulator (the intensity of the magnetic field and the undulator period).

Excitation of a wake field by a relativistic electron bunch in a semi-infinite dielectric waveguide

A wake field excited by a relativistic electron bunch in a semi-infinite metal waveguide filled with a dielectric consists of the Vavilov-Cherenkov radiation, the “quenching”-wave field, and transient radiation, which interfere with each other. An exact analytic expression for the transient component of the field of a thin relativistic annular bunch is derived for the first time. The evolution of the space distribution of a field excited by a finite-size electron bunch is numerically calculated. The excitation of the wake field by a periodic train of electron bunches in a finite-length waveguide is studied.

Wakefield excitation by a relativistic electron bunch in a magnetized plasma

The excitation of a wake wave by a relativistic electron beam in an unbounded magnetized plasma and a plasma waveguide is studied theoretically. It is shown that, in a waveguide partially filled with a plasma, the energy that the electrons of the accelerated beam can gain is 37 times higher than the energy of the electrons of the beam generating wakefield.