P. V. Petrov

Microwave generation using a superluminal source

The power produced by existing sources of microwave radiation falls off with decreasing wavelength. To solve this problem a new concept is proposed for generating microwave radiation, based on the use of a superluminal source formed when electrons are emitted into vacuum from a medium and the emission front propagates along the surface with a speed greater than that of light. Such generators are shown to have a number of completely unique properties: they radiate extremely short pulses (as short as picoseconds); their power exceeds that of existing sources by orders of magnitude; and unlike existing sources, it increases as the wavelength is reduced.

Photoemission pulsed source of wide-band directional electromagnetic radiation

Generation of wide-band directional electromagnetic radiation arising when the pulsed X radiation front strikes the photocathode of a planar diode at an angle is analyzed. The results of numerical simulation are compared with the experimental data obtained with the Iskra-5 setup, which is used for generation of a laser plasma as an X-ray source.

Microwave generation by a superluminal source at ultimate current densities

It is well known that high-power directed wideband electromagnetic radiation in the microwave range can be generated by a superluminal pulse of the electron emission current. The operation of a simple emitting element driven by a superluminal current pulse and consisting of an accelerating diode with a photocathode and a source of ionizing radiation that initiates electron emission from the cathode is considered. It is shown that the parameters of an elementary superluminal source obey scaling relations that are determined by the growth rate of the electron emission current from the photocathode and the parameters of the accelerating diode. The limiting anode current density and the limiting values of the characteristics of electromagnetic radiation achievable in such a system are determined. The effect of the finite dimensions of the accelerating system on the parameters of the emitter is investigated, and the spatiotemporal characteristics of the generated electromagnetic fields are obtained.

Concrete-surface destruction by powerful microwave-radiation pulses

The destruction of the surface layer of concrete by a powerful microwave-radiation pulse is studied. The conditions for the occurrence of shear and spall fractures in concrete at a given depth are found. The range of electrodynamic parameters within which microwave radiation is the most effective for disintegration of concrete is found. The requirements for a microwave generator that permit one to study experimentally the force action of electromagnetic radiation on concrete are formulated.

A high-gradient accelerator based on a faster-than-light radiation source

A wide-band microwave generator using a faster-than-light source is proposed to be used as a charged particle accelerator. According to theoretical estimates, an electric field amplitude as high as ∼1011 V/m or more can be attained at the focus of a paraboloidal emitting surface with a focal parameter of ∼1 m. These estimates are supported by numerical calculations. The schematic diagram of such an accelerator is suggested.

Experimental and Theoretical Investigation of Directional Wideband Electromagnetic Pulse Photoemission Generator

The effect of electromagnetic wave generation by the electric current pulse propagating at the superluminal velocity along a conducting surface might be promising to create a high-power wideband microwave generator. The system comprising a plane vacuum photodiode with a transparent anode and using laser radiation to initialize electron emission is a variant to realize this scheme of electromagnetic pulse generation. This chapter presents results of experimental researches in characteristics of such radiating element with the cesium-antimonide cathode of O50 mm. The performed researches have shown that the generated wideband pulse (\(f_0 \approx 3.3\,\,{\rm{GHz}},\;\Delta f/f_0 \sim 1\)) propagates in the direction corresponding to specular reflection of the incident laser radiation. Under the voltage of about 50 kV the electric field strength of 44 kV/m at the distance of 1.3 m has been recorded that corresponds to the generator power ∼10 MW.

Simulation of microwave generation using the superluminal source

Summary form only given. The power produced by existing sources of microwave radiation falls off with decreasing wavelength. This is conditioned by the fact that as the wavelength is decreased the size of the region (where the energy which can be radiated is stored) decreases. To solve this problem a new concept is proposed for generating microwave radiation, based on the use of a superluminal source formed when electrons are emitted into vacuum from a medium and the emission front propagates along the surface with a speed greater than that of light. Hence the duration of radiation coincides with the time of electron layer formation, which evidently is defined by the electron Langmuir frequency.

On the possibility of concrete destruction under high-power microwaves generated by e-beam

A potential cleaning method for polluted construction surfaces by high-power pulses of microwave radiation may be based on the destruction of a surface thin layer by the action of shock waves generated due to dissipation of microwave energy. When defining the possibility of concrete plane layer destruction by a high-power microwave radiation flux it should be stressed that dry concrete (being a dielectric material) conducts electromagnetic radiation rather well (specific resistance is more than 10/sup 3/ Ohm.m), but shock wave generation and fragment formation under its action occurs most intensively for local energy release. The main prime problem is to create a small region in a material capable under microwave pulses to generate a shock wave which has the ability to cause fragmentation on a sample surface. Such a region should have increased conductivity which ensures the creation of the region with high energy density. The creation of such a region can be available, for example, by saturation of the concrete surface with a conductive salt solution, as it is known that concrete has a water absorption from 4-8% up to 30-40% of its mass. Current experiments show that the specific resistance of a concrete region is equal to 50 Ohm. m, and the skin length, corresponding to 4 mm wavelength electromagnetic radiation, is 1.2 cm.