In this paper, we present the of theoretical calculation and experimental study results of ultrashort pulse emitters with radiating elements based on an oscillator and disk-cone antenna, the excitation source of which is current oscillations in a long line switched by a switch with short switching time τ. The temporal characteristics of the emission field and its spectrum are determined. Depending on parameter l/(cτ) (l is the length of the vibrator arm), various emission modes are shown to be implemented that differ in frequency characteristics and the shape of the radiation pattern. The basic emission regularities are qualitatively explained based on the calculation of the spectrum of eigen oscillations (in the spectral region) and based on the summation of the contributions from elementary currents flowing over the emitter surface (in the time domain).

A generator of repetitive voltage pulses in the form of a damped sine wave with a period of ~6 ns, an amplitude of the first voltage half-wave of up to ~400 kV, and a pulse repetition frequency of up to 60 Hz is described. The generator is powered from a storage battery (7 A h, 36 V) and has several voltage build-up stages.

Описан частотный генератор импульсов напряжения в виде затухающей синусоиды с периодом ~6 нс, амплитудой первой полуволны напряжения до ~ 400 кВ и частотой импульсов до 60 Гц. Генератор питается от аккумуляторной батареи (7 А · ч, 36 В) и имеет несколько ступеней повышения напряжения.

A new design of powerful high-voltage high-current impulse source for nanosecond megavolt charging of short forming lines (SFLs) is proposed. The first stage of the device is based on inductive energy storage. It accumulates energy supplied by the current of magnetic flux compression generator (MCG), whereas the electro-explosive opening switch is used for the energy output into intermediate SFL. In the second stage, we use a Tesla transformer with oil insulation. The results of the earlier experimental study of submegavolt charging of intermediate forming line as well as the results of calculations of the two-stage facility given in this paper demonstrate the feasibility of the device based on MCGs for nanosecond charging of SFL up to about 3 MV.

This study is a contribution into the development of physicotechnical foundations for generation of powerful nanosecond high-current pulses on the basis of explosively driven magnetic flux compression generators. This problem is solved by using inductive storage of energy for matching comparatively low-voltage explosively driven magnetic flux compression generators and high-impedance loads; short forming lines and vacuum diodes. Experimental data of charging of forming lines are given.

Design and characteristics of compact powerful nanosecond UWB pulse source intended for study of particular electromagnetic compatibility problems are given. For excitation of dipole antenna we use high voltage drive-pulse generator with voltage output of UG≈550 kV. Power supply is a set of rechargeable batteries. Designed source of radiation is characterized by the following parameters: field range product (FRP = E×R) equals to 700 kV (with parabolic reflector about 1.2×1.2×0.6 m overall). Peak of radiation spectrum is at the frequency of 0.3 GHz. Pulse-repetition frequency is up to 1 kHz. The source as a whole is combined into monoblock of 1 m high and 0.24 m in diameter. Total weight of the source is 65 kg approximately.

Experimental results of generating a nanosecond high-current pulse burst by a multiwinding dynamic transformer, which is based on the principle of recuperation of the energy stored in the single primary winding, and the method of the sequential magnetic-flux trapping by several secondary windings are described. The inductive energy storage with an opening switch is used to sharpen current pulses of the generator. Six small electric capacitors are in turn charged up to ∼300 kV for ∼100 ns with a time interval of 10 μs.

The work concerns the development of a simple small-size instrumentation antenna for measurements of power density and radiation pattern of different RF sources.

The compact antenna for powerful autonomous portable wide-band systems used, in particular, for studying of electromagnetic compatibility problems was designed. In the given paper some characteristics and results of experiments from this ultra-wideband (UWB) antenna are presented.

We describe an off-line nanosecond charging device for a short forming line; the device has been created on the basis of an inductive energy storage unit. Energy storage is carried out by the current of an explosive magnetic cumulation generator, and the energy output to the load, by means of an electroexplosive current interrupter. The use of a two-stage, instead of a one-stage, magnetic cumulation generator, consisting of a preamplifier and a dynamic transformer, and two smaller-size generators with sequential connection of secondary windings of dynamic transformers, one of which is connected to the inductive storage unit, and the other, to the current interrupter—has made it possible to substantially increase the line charge voltage. As a result, within a time on the order of 100 ns, it was possible to charge a forming line with an electric length of 5 ns to a voltage of ≥1 MV.

In the report compact pulsed oscillator powered by 150 kV voltage source with control pulse repetition frequency from single-pulse modes up to 800 Hz is described. Hertz radiator with parabolic reflector has been used in the oscillator.

A design-experimental study of a magnetic cumulation generator (further referred to as generator) with flat helical is performed. This generator combines advantages of both spiral-cylindrical and disk generators. As to speed of operation, the spiral-radial generator is equivalent to the disk generator, but can operate in high-impedance loads. To calculate characteristics of spiral-radial generators, including external-excitation generators, a semiempirical procedure for determining laws of variations of the inductances and mutual inductance of helical of the generator is developed. The procedure is based on measuring the current oscillation frequency in the course of the magnetic-field compression, while the helix is loaded into a small capacitance. A satisfactory compliance of the experimental data and semiempirical calculations is obtained. The experimental effective time values of the current buildup of the spiral-radial generators do not exceed the same characteristic for spiral-cylindrical generators with an axial charge initiation of the explosive material. A possibility of further decreasing the effective time is shown for the plane-parallel throwing of liner plates.

Presented in this paper is the review of compact electromagnetic pulse generators on the basis of high-voltage (up to 320 kV) repetitive pulse sources. The sources developed in JIHT RAS are adjusted for pulse repetition frequency from the single pulse mode to 400 Hz.

Described in this paper is a compact pulsed oscillator powered by high voltage source for up to 320 kV with pulse repetition frequency control from single-pulse mode up to 40 Hz. Radiator of Hertz dipole type was used as a load

High-power microwave radiation has been generated using a relativistic backward wave oscillator (BWO) powered by a high voltage source comprising an inductive energy storage and an electric-explosion current switch. The high voltage source and the BWO magnetic system are energy pumped by explosive magnetocumulative generators. In experiments, the proposed setup generated 30-ns single-mode radiation pulses with a carrier frequency of 3.6 GHz at an output power of 0.75 GW.

The methods used for reflex triode oscillation frequency tuning within the range of 1.8-2.8 GHz are described. Reflex triode was driven by the generator with output voltage of 600 kV capable to deliver 25 kA current into the load. Radiated pulse energy in both single pulse mode and pulse repetition mode of operation (pulse repetition rate 1 Hz) was about 4 J

At present, high-current relativistic electron beam accelerators are rather bulky devices. Basically, this is determined by the relatively low energy stored per unit mass of capacitors - the main storage in overwhelming majority of accelerator designs. Magnetic cumulative generator (MCG) as energy source together with high-voltage pulse generator on the basis of inductive storage (IS) and electro-explosive opening switch (EEOS) allows abandoning bulky capacitive storages at all and developing compact accelerators capable to generate voltages at Megavolt level. Relatively low efficiency of pulse compression circuit caused by considerable energy losses in EEOS is not a problem, since high energy gain ratio of MCG makes up for it easily. Much more complicated problem is MCG matching to high-inductive load. For efficient operation of EEOS MCG must be capable to generate current pulse with effective length of a few microseconds only and e.m.f. better than 50 kV. Carried out both mathematical and physical simulations contributed into successful solution of given problem. In result, a generator of ~0.1 m3 in volume (including MCG) is developed, which is capable to produce voltage pulses of above 800 kV and energy about 1-2 kJ. Installation was used for generation of high-voltage pulses on the capacitive load, as well as for driving microwave generators, such as resonant relativistic BWO and reflex triode.

The paper describes the installation and experimental results of high-power microwave generation by a resonant relativistic BWO (3.6 GHz, TM/sub 01/) (Kitsanov, S.A. et al., Proc. 14th Int. Conf. on High Power Particle Beams, p.255-8, 2002) driven by a high-voltage generator based on inductive storage (cable line) and an electro-explosive opening switch. As a primary source, either capacitive storage (surge current generator) or magnetic cumulative generator (MCG) was used. For a cathode voltage of 700 kV and diode current of 9 kA, the peak microwave power reached about 0.5 GW and pulse duration was about 50 ns.