The results of the last (in the thermonuclear program “Magnetic compression”) MAGO-IX experiment with a plasma chamber including a third compartment designed to compress plasma with a converging liner are presented. An X-ray pulse consisting of an intense peak of 1-μs duration, followed by a low-intensity tail with a duration of more than 10 μs, was recorded. In the MAGO-IX experiment, the neutrons were generated mainly in the third compartment. A neutron yield of 2 × 1012 was obtained. The results demonstrate that the expected compression of preheated plasma in chambers similar to MAGO-IX is promising for achieving thermonuclear ignition.

This chapter contains sections titled: Introduction Corpuscular and Optical Umbra, Corpuscular Penumbra Magnetosheath and Near-Planetary Shock Wave Discussion Conclusions

When solving some physical problems, in particular, when studing the dynamic characteristics of solid liners accelerated by magnetic field, highpower magnetic energy sources with controlled time of current rising in the load are needed. The helical explosive-magnetic generators equipped with explosive opening switches are commonly used in our experiments. Such sources produce the energy of tens megajoules (1) and transmit it to the load in a matter of microseconds.

The results of the research of the switching parameters of three types of explosive current opening switches used for the energy output from the inductive storages to the load in a microsecond time range are presented. The operation of the current opening switches with foil and ribbed barrier, with foil and barrier the ribs of which have metal patches, and the opening switches on dielectric jet-streams has been studied.

The design and the results of testing of an explosive device forming a current pulse of quasi-trapezoidal shape with the given amplitude and duration in the liner load are presented. A need for such devices was caused by a necessity to compare the experimental data obtained on the gas guns with the results of the experiments with a magnetic drive of the liners under the effect of current flowing through the liner. The results of the experiments in which the formed current pulse in the driven liner had the amplitude of 5 MA, the base duration of 10 ¿s, and the duration of the leading and trailing edges of 2 ¿s are presented.

This paper studied the process of implosion of the solid quasi-spherical liner driven by the axial magnetic field generated by the pulsed power source. In the experiment the pulsed power source comprising the helical EMG, the current opening switch and the transmission line provided the current pulse of 13 MA with the rise time of ~10 mus in the liner load. Two radiographic images of the quasi-spherical liner collapsing to the central axis under the effect of the magnetic field forces were obtained at different time moments. The velocity of the inner surface of the quasi-spherical liner at the moment of focusing was ~ 9 km/s. The parameters of the pulsed power source and the image of the imploding quasi-spherical liner obtained experimentally agree well with the calculated values.

The paper presents the results of application of the explosive magnetic pulsed power source (EMPPS), in the first experiments studying the spallation mechanisms of the solid substances damage under conditions of converging axisymmetric geometry of loading of samples by the impact of the cylindrical liner driven to a velocity of 0,2-1 km/s.

The source of high-voltage pulses. described in the paper. is a two-stage sharpening system that consists of a helical explosive magnetic generator and explosive and electroexplosive current opening switches separated by a current transformer. The helical explosive magnetic generator provides a stored energy of 1 MJ at a current of /spl sim/1.5 MA and a rise time of 40E10/sup -6/ s in an inductive load of 1E10/sup 6/ H. The cascade of the explosive current opening switch and the transformer reduce the pulse duration to 1E10/sup -6/ s. The electroexplosive opening switch is made from thin copper wires placed between layers of polyethylene insulation. The total length of the explosive magnetic pulsed power generator is about 3 m, its diameter being 300 mm. The voltage pulse, with 1.2 MV amplitude and 0.3E10/sup -6/ s duration, has been recorded on the output electrode at a connected load with an impedance of 15 Ohm.

Summary form only given, as follows. The source of high-voltage pulses, described in the paper, is a two-stage sharpening system that consists of a helical explosive magnetic generator, of explosive and electroexplosive current opening switches separated by a current transformer. The helical explosive magnetic generator provides the stored energy of 1 MJ at the current of /spl sim/1.5 MA and the rise time of 40 microsec in the inductive load of 1 microH. The cascade of the explosive current opening switch and the transformer reduces the pulse duration to 1 microsec. An electroexplosive opening switch is made from thin copper wires placed between the layers of polyethylene insulation. The total length of the explosive magnetic generator of pulses is about 3 m the diameter is 300 mm. The voltage pulse with 1.2 MV and 0.3 microsec duration has been recorded on the output electrode at a connected load with the impedance of 15 Ohm.

A device is being considered consisting of a helical explosive magnetic generator, a cascade of explosive and electroexplosive opening switches. This device serves to obtain a single pulse or a group of voltage pulses with the amplitude of up to 1 MV and a duration of several hundred nanoseconds in loads having an impedance of 1-15 Ohm. The interval between the pulses is equal to several microseconds. The electroexplosive cascade contains the given (in accordance with a required number of pulses) number of steps of conductor having different cross-sections and lengths. Amplitude, shape of pulses and the interval between them may be within certain limits changed by the way of picking out the conversion cascades' design parameters. The authors have modelled the operation of the exit cascade of the considered device powered by a capacitor facility. Copper wire, having several parts of different cross-sections, was used as the electroexplosive opening switch. Oscillograms with two and three consecutive pulses with an amplitude of about 550 kV and a duration of less than 500 ns were obtained. The interval between the pulses was about 2 /spl mu/s.