Explosive Magnetic Generator Research Articles

On the Possibility of Achieving Thermonuclear Ignition During Magnetic Compression of High-Temperature Magnetized Plasma by the Current of a Disk Explosive Magnetic Generator

One of the directions for achieving thermonuclear ignition is compression of a heated, magnetized plasma by a liner. This concept was developed in the USA at the Z Machine (MagLIF project). To achieve ignition, it is necessary to create a current pulse with an amplitude of 60 MA or higher. The Z Machine produces currents with amplitudes up to 25 MA. The development of more powerful installations is a problem for the future. At the same time, today already, the explosive magnetic generators create the required currents with long current rise times. In this work, based on calculation results of the compression of a hot magnetized plasma, the possibilities of achieving ignition using modern disc explosive magnetic generators are discussed.

On the Possibility of Achieving Thermonuclear Ignition During Magnetic Compression of High-Temperature Magnetized Plasma by the Current of a Disk Explosive Magnetic Generator

On the Possibility of Achieving Thermonuclear Ignition During Magnetic Compression of High-Temperature Magnetized Plasma by the Current of a Disk Explosive Magnetic Generator

ДВУСПИРАЛЬНЫЙ МАГНИТОКУМУЛЯТИВНЫЙ ИСТОЧНИК СВЕРХСИЛЬНЫХ МАГНИТНЫХ ПОЛЕЙ

The relevance At present, the issues of creating an original design of a highly efficient explosive magnetic (magnetocumulative) generator, developing its mathematical model and conducting experimental research in this direction are topical in science and technology. Aim of research Consider the possibility of building new aircraft fuel ignition devices based on a double-helix magnetic-cumulative generator, solving the problem of confirming its advantages over known and proven methods by creating a mathematical model. Research methods Literature review and patent study, obtaining a mathematical model with experimental studies on full-scale samples in real operating conditions. In the course of the work, methods of the theory of electrical circuits, magnetic field, elements of mathematical analysis and the theory of electrical oscillatory processes (beats, resonance, etc.) in complex circuits were used. Results As a result, a relation was obtained that determines the maximum value of the beat frequency between two electrical circuits connected by a weak capacitive coupling, which makes it possible to carry out the calculations necessary when creating a magnetocumulative generator with high microwave radiation and during its regulation. Thus, the mathematical model of a magnetocumulative generator presented in the article is based on a fundamentally new combination of the application of the laws of electrodynamics and the theory of electrical oscillatory processes. On the basis of this model, proposals have been developed for using the proposed design with the original circuit design. The results of the work can be used in the ignition system of aircraft at an altitude of more than 20 km, which is a world problem, as well as to improve the efficiency of a shunt reactor, an installation for de-icing, mechanical engineering, medicine, military equipment, radio physics, etc.

Nonlinear Plasma Loads Powered by Explosive Magnetic Generators in the Mode of Increasing Power

Nonlinear Plasma Loads Powered by Explosive Magnetic Generators in the Mode of Increasing Power

MASS AND DIMENSIONAL PARAMETERS OF SHAPERS OF A POWERFUL MICROWAVE ELECTROMAGNETIC FIELD

The questions of preliminary assessment of the possibility of placing shapers of a high‑power microwave electromagnetic field on existing carriers are considered. The volume and mass of the shaper, consisting of an autonomous power source and generator, directly depend on the energy and power of the generated currents and fields. At the same time, the payload of any carrier always has weight and size limitations, which may not allow placing a field shaper with specified radiation parameters on the proposed carrier. The purpose of the work is to determine the laws that connect the volume and mass of the electromagnetic field shaper with the radiation parameters – power, duration, repetition period and number of pulses. The basis for finding the volume and mass of the shaper was the equation of the energy balance in the system «power supply‑generator» for the pulse‑periodic mode, the specific energy parameters of the power supply and the specific power parameters of the generator. In the energy balance equation takes into account idle power losses within pauses between pulses. As a result of solving the problem, expressions are obtained for estimating the volume and mass of the electromagnetic field shaper. Has been determined condition is under which, in the generation mode, sequences of pulses of the same power and duration with a constant repetition period, losses of idle do not affect the mass‑dimensional parameters of the shaper. The volume and mass of the shaper, constructed according to the «explosive magnetic generator – vircator» scheme, were estimated.

USE OF EXPLOSIVE MAGNETIC GENERATORS TO ACCELERATE CONDENSED SHELLS BY THE CASCADING METHOD

A method for reducing the characteristic time of action of the pulse produced by explosive magnetic generators is proposed. An experiment was performed whose results confirm that this method can be used in practice.

Verification of experimental studies of pulsed plasma accelerators

Explosive-magnetic generators (EMGs) unlike capacitive storages (CSs), as a rule, have growing power. The effective operation of pulsed plasma loads, such as pulsed plasma accelerators (PPAs), plasma foci, plasma breakers, etc, can be provided at realization of the mentioned advantage of EMG as a power source. A technique of laboratory experiments with PPA is presented in this paper. The experiments with PPA powered by CS precede the explosive experiment with EMG. The dependencies of the load operation modes on the start parameters are determined by the analysis of the experimental data. They included the dynamics of the inductance and the position of the current shell inside the PPA. The technique allows reducing the number of expensive explosive experiments and supplements the database of nonlinear dependencies of the load parameters under various amplitudes of the current pulse that is important for mathematical modeling. The technique based on experiments together with the estimations allowed solving the problem of matching of non-linear loads type PPA with EMG. Thus, the productivity of experiments with EMG increases greatly. The developed technique can be adapted to a wide class of nonlinear loads.

Source of megaampere current with the rise time ∼100 ns on the basis of explosive magnetic generator

To achieve a thermonuclear ignition threshold in the scheme of indirect irradiation of Z‑pinch by X‑radiation, it is necessary to implode the liner by the current with the amplitude 65 МА for the time 100 ns. The currents with such parameters can be achieved with the use of super-power disk explosive magnetic generators and a two-stage current pulse sharpening system based on foil electrically exploded current opening switches in a form of a serpentine. The implementation of the explosive current source with a rise time of 100 ns is advisable to be carried out in stages by increasing the magnitude of current. The results of the first-stage experiments, in which the current with the amplitude of 5 MA was produced on the basis of the helical explosive magnetic generator in the load of 10 nH for the time of 110 ns, are presented.

Source of a Mega-Ampere Current with ~100-ns Time of Rise Based on an Explosive Magnetic Generator

To achieve the thermonuclear-ignition threshold in the scheme of indirect X-ray irradiation of the Z-pinch, it is necessary to implode the liner by a current with an amplitude of ~65 МА within a time of ~100 ns. Currents with such parameters can be generated using super-power disk-type explosive magnetic generators and a two-stage current pulse-sharpening system based on foil, electrically exploded, “serpentine”-shaped current opening switches. It is reasonable to implement the explosive current source with a rise time of ~100 ns in stages by increasing the current magnitude. The results of the first-stage experiments in which a current with an amplitude of 5 MA is used in an inductive load of ~10 nH with a time of ~120 ns on the basis of the helical explosive magnetic generator are given.

Calculation model of the plasma load matching with the current sources based on explosive magnetic generator

In this paper, we consider the model of engineering calculation for the matching of the explosive-magnetic generators (EMG) and pulsed plasma accelerator (PPA) at amplitudes of currents reaching 2.5 MA. The main features of the model are taking into account the dynamics of change in the inductance of PPA and the using of the concentrated mass approximation for the current shell. The taken assumptions were checked by experimental data on real PPA powered by EMG. It is shown that the built model has sufficient accuracy for preliminary calculations for design and installation of such technique.

Pulse-Current Sources for Plasma Accelerators

The pulse source for plasma-accelerators supply operates under the conditions of nonlinear growth of load inductance, which complicates the matching of the source and the load. This article presents experimental studies of the use of both traditional pulse-energy sources based on capacitive storage and alternative ones based on explosive magnetic generators (EMG). It is shown that the EMG with the special device of the current-pulse formation more effectively matches with such a plasma load as the pulse plasma-accelerator (PPA). This device allows a wide range to manage the current-pulse formation in a variable load and, consequently, to optimize the operation of the power source for the specific plasma load. A mathematical model describing the principle of operation of this device in EMG on inductive load was developed. The key adjustable parameters are the current into the load, the residual inductance of the EMG, and the sample time of the specified inductance and the final current in the load. The device was successfully tested in experiments with the operation on both one and two accelerators connected in parallel. In the experiments, the optimal mode of device operation was found in which the total energy inputted to a pair of accelerators in one pulse reached 0.55 MJ, and the maximum current reached about 3.5 MA. A comparison with the results of experiments performed with capacitive sources of the same level of stored energy is given. The experiments confirmed not only the principal possibility of using EMG with a special device of current-pulse formation for operation with plasma loads in the MJ energy range but also showed the advantages of its application with specific types of plasma load.

Experimental investigation of powerful pulse current generators based on capacitive storage and explosive magnetic generators

Experimental models of microsecond duration powerful generators of current pulses on the basis of explosive magnetic generators and voltage impulse generator have been developed for the electromagnetic pulse effects on energy facilities to verify their stability. Exacerbation of voltage pulse carried out through the use of electro explosive current interrupter made of copper wires with diameters of 80 and 120 μm. Experimental results of these models investigation are represented. Voltage fronts about 100 ns and the electric field strength of 800 kV/m are registered.

Superpower Disk Explosive Magnetic Generators of Electromagnetic Energy for High-Energy Densities Research

Multimodule disk explosive magnetic generators (DEMGs) of microsecond pulses of electromagnetic energy up to hundreds of megajoules, based on the internal explosive energy into electromagnetic energy conversion (magnetic flux compression), are reviewed. Fundamentals of the DEMG operation are outlined. Conventional DEMGs with intricate disk profile are described in short. A numerical technique of DEMG simulations is outlined. Special attention is given to the modernized DEMGs with flat modules of different calibers. At preservation of the output characteristics of the DEMGs with profile discs, the factor of the explosive to electromagnetic energy conversion of the DEMGs with flat discs is twofold higher; such DEMGs achieve higher speeds, represent a technological advance and are less expensive.

Simulations of the Interaction of High-Velocity Condensed-Matter Liners With Walls

This paper presents an overview of publications on numerical simulations of one of the major 2-D effects observed in magnetically driven implosion of cylindrical condensed-matter liners: their interaction with glide planes. We consider liners accelerated to 8-20 km/s by currents of 30-100 MA delivered by disk explosive magnetic flux compression generators with azimuthal magnetic fields of 1-6 MG (magnetic pressures of 0.04-1.4 Mbar): experimental liners HEL-1, ALT-1, 2, and liners HEL-2, ALT-3 proposed for high energy density physics research.

The Sources of Pulse Current Based on Explosive Magnetic Generators for Mobile Testing Facility

This paper demonstrates the practical application of the explosive magnetic generator (EMG) as a source of high-power pulses for mobile testing complex EMG (MTC EMG). Hereinafter, the name of explosion generator is used on a par with the name of helical explosion-magnetic generator. Laboratory sample was brought to a level of modern complex, which is able to solve the applied problems in the grid power systems. MTC EMG is able to reproduce the output currents, similar to lightning currents, so it can be used to simulate a pulse impact on the energy system. The report contains: a description of the basic physical and electrical solutions underlying the construction of the generator of lightning currents, output characteristics, and results of MTC EMG field testing. Optimization of schemes including the different impedances of EMG and inductive resistive load with the use of transformer coupling allowed the effective energy transfer from the EMG to the load. Pulse currents and voltages on the load and also the response of soil between ground loops under the action of lightning currents, generated by MTC EMG, were registered in the testing. Autonomous measuring instruments included in the complex were protected from electromagnetic interference.

A Review of Experimental Progress in the MAGO/MTF Thermonuclear Program

Magnitnoe Obzhatie (MAGO)/magnetized target fusion (MTF) thermonuclear experiments executed with a goal of producing the target plasma heated up to temperatures of hundreds of electronvolts, intended for subsequent compression by an imploding liner accelerated by explosion products, are reviewed. In MAGO/MTF experiments, plasma chambers were used consisting of two or three compartments connected by narrow nozzles: acceleration cylinder compartment and deceleration/fusion compartments (cylindrical or hemispherical). A technology of plasma chamber laboratory conditioning is described. Neutron and soft X-ray pulses are presented and obtained in experiments with chambers powered by an explosive magnetic generator. Irrespective of the chamber geometry and number of compartments, the X-ray pulse consists of a highly intensive peak with a duration of $1~\mu \text{s}$ and more than a 10- $\mu \text{s}$ -long low-intensity tail. The neutron pulse is time coincident with the X-ray peak. Yields up to $10^{13}$ neutrons were detected in experiments with two-compartment chambers. Three-compartment chambers with an intermediate compartment are believed to be more promising for the compression. The results are described of the latter MAGO-IX experiment, the only successful experiment with the three-compartment chamber, in which the yield of $2\times 10^{12}$ neutrons was detected in the third compartment and the yield in the middle compartment was many times lower.

Thermonuclear ignition by Z-pinch X-ray radiation produced by current of an explosive magnetic generator

The scheme of a device based a superpower disk-type magnetic explosion generator to produce a pulse of X-ray radiation with the energy exceeding the target ignition threshold is described and validated.

Fundamentals of Electrodynamic Technique of Numerical Designing of Helical High-Explosive Magnetic Generators

Presented are the fundamentals of a consistently electrodynamic 2-D technique of designing helical explosive magnetic generators by numerical simulation on the basis of nonuniform equation for the vector potential with a priori set right-side term. The technique is demonstrated by solving a 1-D problem. A model 2-D problem a closed coil over a tube is analyzed. A coil current rupture is simulated. Concepts of vacuum inductance and free magnetic flux are discussed. Magnetic flux losses in the skin layer and free magnetic flux variation are calculated for an instant compression of an electric contour. A 2-D nonstationary problem a closed coil over a tube is solved. A critical mode of the generator operation is analyzed. A technique is described for solving a problem multiturn helix over a tube .

Mobile testing complex based on an explosive magnetic generator

A mobile testing complex prototype on the basis of an explosive magnetic generator (MTC EMG) is developed to simulate a lightning current pulse. The main element of this complex is a current pulse generator comprising a EMG with a pulse transformer for energy release into the load. The electric chain of the MTC EMG is theoretically analyzed taking into consideration energy losses in active resistances in the primary circuit of the transformer and the inductive-resistive nature of the load, which resulted in the minimization of energy losses in the primary circuit depending on the electric chain parameters. It was found that, if the energy losses are minimized, the efficiency of transferring the EMG energy into the load exceeds 50%. As a result of the field tests of the MTC EMG, its basic characteristics were determined and the waveforms of the current pulses and voltages in the load were obtained. It is shown that the results of the mathematical simulation of current pulses in the load are in good agreement with the experimental data.

Мобильный испытательный комплекс на основе взрывомагнитного генератора

Мобильный испытательный комплекс на основе взрывомагнитного генератора