V. V. Kladukhin

A high-power nanosecond pulse generator based on solid-state switches

A high-power nanosecond pulse generator based on a Lewis transformer and ultrafast IGBT-transistors is described. The generator ensures the formation of square pulses at a 50-Ω matched load with a repetition rate of up to 2 kHz. The pulse duration may be freely varied from 20 to 200 ns, and the pulse power may vary from 200 W to 2 MW.

Low-impedance relativistic backward wave oscillator

It is shown that the limiting electron-beam current in a relativistic backward wave oscillator (BWO) can be increased using a slow-wave system (SWS) in the form of a circular waveguide with shallow rectangular corrugation. This idea was checked both experimentally and numerically for a 3-cm BWO with a short homogeneously corrugated SWS and a resonance reflector-modulator. The experiments showed that the proposed BWO with an explosion-emission electron gun and said SWS can effectively operate on 60-Ohm electron beams at a gigawatt output power.

Relativistic backward wave oscillator with multijet electron beam

The influence of the multijet structure of an annular electron beam on the operation of a high-current relativistic backward wave oscillator (BWO) has been experimentally studied. Multijet annular electron beams were generated using graphite explosive-emission cathodes shaped as tubes with comb-shaped ridges. It is established that the BWO working characteristics are highly stable with respect to the multijet beam structure. Potential possibilities of using multijet electron beams in BWOs are pointed out.

A high-power nanosecond pulse generator based on a serial wave summator and transistor switches

A high-power nanosecond pulse generator based on a serial (linear) radial-coaxial summing structure and primary partial pulse formers, which are based on high-speed IGBT transistors, is described. The generator has a modular structure in the form of a system of serially connected sections. Each section ensures generation and matched transmission of partial rectangular pulses having a duration of 40–200 ns, a power of 10 kW–1.5 MW, and a voltage of 0.1–1.2 kV with a pulse repetition rate of up to 2 kHz to a summing coaxial waveguide. The generator output parameters are determined by the number of connected sections. The three-section generator, intended for producing rectangular nanosecond pulses with a power of up to 3.5MW, was designed, manufactured, and tested.

A high-power relativistic backward wave oscillator with a longitudinal slot slow-wave system

It is established that longitudinal slots in the slow-wave system of a high-current relativistic backward wave oscillator (BWO) can be used as additional means of mode selection and effective absorption of near-wall plasma. Using these properties, it is possible to increase the limiting pulse duration and repetition rate of BWO output radiation pulses.

Sequential Nanosecond Switch

Summary form only given. This work presents a way to create sequential switches using propagation of the overvoltage wave along a series of switching elements. The process is based on the interaction of three dividing components. The base component consists of switches, which come into action when voltage exceeds their threshold breakdown voltage. Two auxiliary components consist of a series combination of capacitive elements. In the initial state of the sequential switch, the quasi-static electric field generated by an external electric circuit is uniformly distributed over all switch elements. The elements of the base and auxiliary components form coupled circuits, and the coupling between them provides the process of propagation of the overvoltage wave, which is initiated by a short circuit of any switching element. The electric field, which is formed on the wave front, exceeds its initial strength by two or more times. We present a sequential switch realized as a high current multiple gap controlled switch with high pressure gas operating in a regime of multiple-spark nanosecond commutation. Results of experimental investigations of the switch are presented.

A generator of high-power nanosecond pulses based on a modular two-level summator

A modular approach to designing generators of high-power high-voltage nanosecond pulses on the basis of a two-level wave summator and transistor formers of partial pulses is considered. The design and parameters of the modules that are oriented at the development of generators of voltage pulses of up to 300 kV at a current of up to 4 kA are described. The capabilities of these modules are demonstrated based on the example of a pulse generator with a power of 10 MW, a varied pulse duration of 50–150 ns, and a pulse repetition rate of up to 2 kHz.

Relativistic backward-wave tube with a smooth control over output radiation pulse duration

The effect of failure of oscillations in a low-impedance backward-wave tube is described and the possibility of using this effect for controlling the duration of output radiation pulses is considered.

Triggered multigap gas switch with radial arrangement of electrodes

The approach to development of triggered multigap gas switches with radial arrangement of electrodes is described. Gaps switching process is based on self-propagation of overvoltage along the chain of these gaps. Basic features of such type of gap switches were investigated. Switching processes of radial gas switch in nitrogen and SF6 were researched, including dynamics properties, triggering ability, delay of switching process and spatial switch channels distribution. The ability of using these types of devices as the switches of coaxial double forming lines in highcurrent a nanosecond highvoltage pulse generators is shown.

Relativistic BWO with Short Interaction Space

Summary form only given. The results of experimental investigations of two high power relativistic BWOs with short electrodynamic systems and input reflectors that convert an operating wave to a wave extracting radiation from the interaction space, and modulate the electron beam are presented. A variation of the quasi-static potential of the electron beam takes place in the section with deep corrugation of the waveguide wall. This variation significantly alters phase relations and the magnitude of coupling between interacting waves. In the experiments amplitude and phase relations are chosen by varying the length of the drift channel between the reflector and the interaction space and by applying resonant modulators. We have used a system of coupled cavities or a Bragg reflector as a resonant modulator. We also demonstrate that these gigawatt BWO-oscillators can work at high repetition rate and with low impedance (down to 50 Omega) electron beams.