Magnetic Cumulation Generator Research Articles

Cascade Magnetic Cumulation Generator on the Basis of Inductively Coupled Circuits with A Variable Coupling Coefficient

A scheme of a multicascade magnetic cumulation generator based on a dynamic variation of the coupling coefficient of inductively coupled circuits is proposed. Each cascade contains two circuits including two pairs of inductively coupled coils. One pair of coils is subjected to simultaneous deformation, and one of the coils in the other pair is arranged with the opposite connection. It is shown that the energy in the load can be gradually increased (from one cascade to another) by using additional cascades. By an example of a two-cascade system, the proposed circuit is compared to the known circuits of the cascade system design based on the magnetic cumulation principle (generator with a step-up transformer and dynamic transformer). Within the framework of the model that ignores the ohmic resistance of conductors, it is demonstrated that the proposed scheme allows one to obtain a greater energy in the high-inductance load than the schemes with a step-up or dynamic transformer owing to a change in the sign of the magnetic flux in the secondary circuit. It is found that the increase in energy in the new scheme is independent of the coupling coefficient (at high values of this coefficient) and becomes greater as the number of cascades is increased.

Generation of electromagnetic energy in a magnetic cumulation generator with the use of inductively coupled circuits with a variable coupling coefficient

A method of generation of electromagnetic energy and magnetic flux in a magnetic cumulation generator is proposed. The method is based on dynamic variation of the circuit coupling coefficient. This circuit is compared with other available circuits of magnetic energy generation with the help of magnetic cumulation (classical magnetic cumulation generator, generator with transformer coupling, and generator with a dynamic transformer). It is demonstrated that the proposed method allows obtaining high values of magnetic energy. The proposed circuit is found to be more effective than the known transformer circuit. Experiments on electromagnetic energy generation are performed, which demonstrate the efficiency of the proposed method.

Generation of Electromagnetic Energy in a Magnetic Cumulation Generator with the use of Inductively Coupled Circuits with a Variable Coupling Coefficient

Generation of Electromagnetic Energy in a Magnetic Cumulation Generator with the use of Inductively Coupled Circuits with a Variable Coupling Coefficient

A mobile test facility based on a magnetic cumulative generator to study the stability of the power plants under impact of lightning currents

The report presents the results of the development and field testing of a mobile test facility based on a helical magnetic cumulative generator (MCGTF). The system is designed for full-scale modeling of lightning currents to study the safety of power plants of any type, including nuclear power plants. Advanced technologies of high-energy physics for solving both engineering and applied problems underlie this pilot project. The energy from the magnetic cumulative generator (MCG) is transferred to a high-impedance load with high efficiency of more than 50% using pulse transformer coupling. Modeling of the dynamics of the MEG that operates in a circuit with lumped parameters allows one to apply the law of inductance output during operation of the MCG, thus providing the required front of the current pulse in the load without using any switches. The results of field testing of the MCGTF are presented for both the ground loop and the model load. The ground loop generates a load resistance of 2–4 Ω. In the tests, the ohmic resistance of the model load is 10 Ω. It is shown that the current pulse parameters recorded in the resistive-inductive load are close to the calculated values.

Magneto-hydrodynamic calculation of magnetic flux compression with explosion driven solid liners and analysis of quasi-isentropic process

Magnetic cumulative generator (MC-1) is a kind of high energy density dynamic device. A liner is driven by a cylinderical explosive implosion to compress the magnetic flux preset in the cavity. Then the chemical energy is converted into magnetic one, which is cumulated nearby the axis to form ultra-intense magnetic field used to load sample in non-touch manner. This loading technique can bring higher pressure and relatively low elevated temperature in the sample and has a very high-degree isentropy in the course of compression. The configuration magneto-hydrodynamic code SSS/MHD is used to develop one-dimensional magneto-hydrodynamic calculation of magnetic flux compression with explosion driven solid liner. The calculation results of magnetic field in cavity and velocity of inner wall of sample tube are obtained and accord with the magnetic field measured by probe and the velocity measured by laser interference. The buckling and Bell-Plesset instabilization produced by linerly compressing magnetic field are shown through frame photography. The change laws of magnetic diffusion, eddy current and magnetic pressure in liner and sample tube are analyzed, which show that the magnetic field and pressure and eddy near to cavity in the sample tube are all higher than the ones in the liner with the same distance to cavity. The balance between the electromagnetism force and implosion action and the difference between sample tube and liner velocities are the main reasons under imploding movement. The change of isentropic increment with compression degree at the same location, whose distance is 0.05 mm to magnetic cavity in the sample tube, is discussed. The result indicates that the ratio of the maximum increment to specific heat of sample tube material is about 10%, which shows that the process of compression magnetic flux with explosion is quasi-isentropic. In general, SSS/MHD code can reveal in depth the physic images which are difficult to measure or observe in the magneto-hydrodynamics experiment.

Magnetic cummulation generators applied for rapid charging of forming lines

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.

A helical-radial magnetic cumulation fast-growing current pulse generator

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.

A Helical Magnetic-Cumulation Generator with a Compact Transformer

Experimental data on a helical magnetic-cumulation generator with an output step-up transformer formed by two coaxial solenoids is presented. The inner diameter of the helix is 50 mm. Compared with the transformers described earlier, this transformer has a smaller size. The transformer can feed an energy of ∼1 kJ into a ∼100-μH high-impedance load.

Structure and dynamics of a plasma piston in rail-gun accelerators for solid objects

of megagauss magnetic fields," Zh. Prikl. Mekh. Tekh. Fiz., No. 3 (1987). 55. K. Nagayama and T. Mashimo, "Explosive-driven magnetic flux cumulation by the propagation of shock compressed conductive region in highly porous metal powders," J. Appl. Phys., 61, No. i0 (1987). 56. A. D. Sakharov, R. Z. Lyudaev, E. I. Smirnov, et al., "Magnetic cumulation," Dokl. Akad. Nauk SSSR, 165, No. 1 (1965). 57. C.M. Fowler, R. S. Caird, and W. B. Carn, "Production of very high magnetic fields by explosion," J. Appl. Phys., 31, No. 3 (1960). 58. A. I. Pavlovskii, N. P. Kolokol'chikov, M. I. Dolotenko, et al., "Cascade magnetic cumulation generator of superstrong magnetic fields," in: Superstrong Magnetic Fields: Proc3rd Int. Conf. on the Generation of Megagauss Magnetic Fields, Nauka, Moscow (1984)o 59. A. I. Pavlovskii, A. I. Bykov, M. I. Dolotenko, et al., "Limiting value of reproducible magnetic field in cascade generator MC-I," in: Megagauss Technology and Pulsed Power Applications: Proc. 4th Int. Conf. on Megagauss Magnetic Field Generation, New York (1987).

Organic dye laser with excitation from a magnetic cumulation generator

Organic dye laser with excitation from a magnetic cumulation generator

Transformer coupling of inductive and resistive loads to a magnetic cumulation generator

Transformer coupling of inductive and resistive loads to a magnetic cumulation generator

Operation of a magnetic cumulation generator into a capacitative load

Operation of a magnetic cumulation generator into a capacitative load