Experimental estimates of the process of the ejection of particles and the formation of plasma during the shock wave exits on the free surface of the cooper sample studied were carried out. The radiation intensity was recorded by a three-channel pulsed pyrometer in an experimental assembly with lateral observation. When the impactor speed was about 5 km/s, a stream of particles and plasma flew from the target surface, the front speed of which reached 12.5 km/s.

Experiments on initiation of nitromethane sensitized by diethylenetriamine in weight proportion 98/2 by exploding wires were conducted. Several conditions of initiation of low speed detonation were determined.

Measurability of liner inner surface brightness temperature by two channel optical pyrometer is shown. Liner is compressed by detonation products in large-scale experiment. Absolute radiant intensity values were obtained by measuring optical system channel calibration involving tungsten and xenon radiation sources. Three ways of surface brightness temperature measurement are presented at wavelengths of 620 and 850 nm. Using the developed procedure copper and steel liners behavior (brightness temperature, average speed) under compression by detonation products are evaluated.

The results of experimental study of two-stage explosive magnetic generator with magnetic flux trapping (EMG MFT) and opening switch in the primary circuit are presented. It was shown that this type of generator demands less than 3 μs to achieve the maximum of current derivative (30 - 100 kA/μs) and maximum of the output voltage. The generators with such parameters are necessary for a number of loads, for example, for the plasma accelerator with growing inductance. At the same time the problem of emerging surge in the secondary circuit of the generator was solved through the introduction of a separate single-turn closing switch with high breakdown voltage. The comparison of the performance of two types of EMG MFT is described. The first type generator was with opening switch in the primary circuit, the second one was without breaking of the primary circuit. They had approximately the same initial input parameters (inductances of the primary and the secondary circuits and the coupling coefficients) and the same inductance of model load - 1.16 μH.

The processes associated with the arrival of a strong shock wave at the surface of a metal have been considered. It has been experimentally revealed that the withdrawal of the wave from a shock-loaded sample under release is accompanied by the formation of not only a dusty flow, but also a metal plasma. The temperature of the plasma component, which is about 1 eV, has been determined from the relation of the line intensities using the spectral diagnostics of the plasma.

Results are given of theoretical and experimental investigations of schemes of matching of magnetocumulative generator (MCG) and load, which include a helical MCG, storage inductance coils, solid-state switch, and explosive current breaker. Magnetocumulative generators in combination with constant and variable storage inductances are developed and investigated. The results of numerical studies are checked in experimental runs under a model load with inductance of 100 nH and under a load with variable inductance. The possibility is demonstrated of using the MCG developed as the effective power supply for a pulsed plasma accelerator (PPA).

Представлены результаты теоретических и экспериментальных исследований схем согласования взрывомагнитного генератора (ВМГ) и нагрузки, включающих спиральный ВМГ, накопительные индуктивности, твердотельный замыкатель и взрывной прерыватель тока. Pазработаны и исследованы ВМГ в сочетании с постоянными и переменными накопительными индуктивностями. Расчетные исследования проверены в экспериментальных пусках на модельную нагрузку с индуктивностью 100 нГн и на нагрузку с переменной индуктивностью. Показана возможность применения ВМГ разработанной конструкции в качестве эффективного источника питания импульсного плазменного ускорителя (ИПУ).

Megagauss Magnetic Field Generation, Its Application to Science and Ultra-High Pulsed-Power Technology, pp. 312-315 (2004) No AccessMEASUREMENTS OF DENSE PLASMA PARAMETERS BY THE INTERACTION OF PLASMA WITH STRONG MAGNETIC FIELDV. B. MINTSEV, S. V. DUDIN, V. K. GRYAZNOV, A. E. USHNURTSEV, N. S. SHILKIN, and V. E. FORTOVV. B. MINTSEVInstitute for Chemical Physics Research RAS, Chenogolovka, Russia, S. V. DUDINInstitute for Chemical Physics Research RAS, Chenogolovka, Russia, V. K. GRYAZNOVInstitute for Chemical Physics Research RAS, Chenogolovka, Russia, A. E. USHNURTSEVInstitute for Chemical Physics Research RAS, Chenogolovka, Russia, N. S. SHILKINInstitute for Chemical Physics Research RAS, Chenogolovka, Russia, and V. E. FORTOVInstitute for Chemical Physics Research RAS, Chenogolovka, Russiahttps://doi.org/10.1142/9789812702517_0062Cited by:0 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: Experiments on measurements of the electron concentration and electrical conductivity in weakly non-ideal dense helium plasma were carried out by the interaction of plasma with a strong magnetic field. Explosively driven shock tubes were used for plasma generation. To obtain a strong magnetic field a solenoid was wound over the tube. To avoid plasma heating by the electrical field eddy current, a high level of conductivity was generated behind the reflected shock wave. Electron concentration was defined by measurements of Hall voltage. The four-point probe method was used to measure electrical conductivity. Experimental data are compared with the calculations. FiguresReferencesRelatedDetails Recommended Megagauss Magnetic Field Generation, Its Application to Science and Ultra-High Pulsed-Power TechnologyMetrics History PDF download

Transformer schemes matching magnetocumulative generators (MCG) with high impedance loads, like vircator, look promising for achieving long pulse duration of 1 ps. An analysis of expected parameters is made here. The necessary MCG and transformer parameters are discussed and the experimental set-up is described. The shots with the MCG simulator were carried out first. At simulator voltage 40 kV and reserved energy 12 kJ, the voltage pulse with amplitude to 600 kV and 320 ns duration is generated on a triode with a virtual cathode. Microwave radiation of 300-400 MW and 200-300 ns duration is generated within a 10 cm wavelength range.

Several types of multi-stage flux-trapping helical flux compression generators for high impedance loads are considered. Short-pulse two-stage helical generators with diameter 100 mm and initial energy of 0.5-3 kJ have supplied energy up to 40 kJ into a 5-/spl mu/H inductive load in a time of about 15 /spl mu/s. Long-pulse two-stage generators with final helix diameter of 110 mm initial energy of 0.8-2.7 kJ have supplied energy up to 350 kJ into a 0.3-/spl mu/H inductive load. Long-pulse three-stage generators with final helix diameter of 160 mm and initial energy of approximately 5 kJ have supplied up to 700 kJ into a 0.5-/spl mu/H inductive load. Model generators without flux trapping and with final helix diameter of 160 mm and initial energy of approximately 20 kJ have supplied energy up to 1.0 MJ into a 0.5 /spl mu/H inductive load. Long-pulse two-stage generators with final helix diameter of 160 mm and initial energy of approximately 30 kJ produce energy up to 1.6 MJ in a load of 0.5 /spl mu/H.

The Hall effect parameters in shock compressed air, helium and xenon have been estimated and results of experiments with air and helium plasma are presented. Explosively driven shock tubes were used for the generation of strong shock waves. To obtain magnetic field a solenoid was winded over the shock tube. Calculations of dense shock compressed plasma parameters were carried out to plan the experiments. In the experiments with the magnetic field of ∼5 T it was found, that air plasma slug was significantly heated by the whirlwind electrical field. The reflected shock waves technique was used in the experiments with helium. Results on measurements of electrical conductivity and electron concentration of helium are presented.

We examine models of the operation of magnetoexplosive generators with magnetic flux constriction [compression] with inductive-ohmic load and analyze the limiting parameters of the devices. We model the operation of generators with axisymmetric liner expansion and generators with sliding contact point. Various approximations for description of the time dependence of the circuit parameters are discussed. The calculated shapes of the current and voltage pulses in the load are compared with the experimental data.

Experiments are presented on the operation of compact explosive magnetic generators with magnetic flux trapping in high inductive loads L = 1-45 muH, with the goal of obtaining electromagnetic energy pulses up to 10 kJ over a time of approximately 10 musec. Equipment requirements are examined, and designs with axial initiation, as well as cylindrical and conical generators with a sliding contact point, are investigated. One stage produced amplification factors of lambda congruent-to 6 for the magnetic flux and psi congruent-to 20 for the energy for a given energy and power level.

Experiments in the generation of a relativistic electron beam and pulsed microwave radiation using the energy of chemical explosives were performed. A vircator based on a triode with a virtual cathode was chosen as the microwave generator. For transformation of the explosion energy into electromagnetic energy, high voltage magnetocumulative generators with magnetic flux interception energized by helical magnetocumulative generators were developed. Electric-fuze circuit breakers were used to match the impedances of the magnetocumulative generators and the vircator, as well as to form the necessary shape of the electrical pulse. As a result, voltage pulses of up to 600 kV with the rise time congruent-to 60 ns were applied to the vircator, and the current amplitude in the triode reached 16 kA. The peak power of microwave radiation brought out into the atmosphere was at least 100 MW. A model is proposed that describes the performance of the circuit and its elements, and its reasonable agreement with experiment is shown.