MHD-nozzle device as a thermonuclear target in MAGO/MTF concept Demin, A.N.; Chernyshev, V.K.; Korchagin, V.P. ...
12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103),
1998, Volume:
2
Conference Proceeding
Describes the MAGO-MTF (magnetised target fusion) approach to fusion energy using a MHD-nozzle device as the thermonuclear target. In MAGO-MTF, thermonuclear reaction ignition has two stages: 1) ...heated magnetized plasma formation; and 2) adiabatic compression of the obtained plasma and the achievement of thermonuclear reaction burning conditions. The formation of plasma with definite temperature and lifetime is carried out by means of plasma acceleration up to ultrahigh velocities in the MHD Laval nozzle under the influence of quick-increasing magnetic field pressure and by means of the further plasma thermalisation. Some results of the MHD-nozzle device calculations are presented, in which one can see the character of plasma motion and the dynamics of its heating.
Experimental study of Rayleigh Taylor instability by means of magnetic implosion Azra, A.; Baclet, P.; Buchet, J. ...
PPPS-2001 Pulsed Power Plasma Science 2001. 28th IEEE International Conference on Plasma Science and 13th IEEE International Pulsed Power Conference. Digest of Papers (Cat. No.01CH37251),
2001, Volume:
1
Conference Proceeding
Rayleigh-Taylor instability (RTI) in imploding devices is to be studied if to define ICF targets. Direct use of explosive as a propellant was tested by the past to analyse RTI effects. Drawbacks of ...corresponding devices are well known: side effects, high areal masses inducing accuracy limitation in transverse radiographic observation, no simple way for pressure level modulation. They can be avoided by the use of magnetic driver and relevant device design, hereafter described. This paper presents results of a joint CEA/VNIIEF experiment dedicated to this topic. Potok type EMG with FOS was used to provide 7-8 MA current law within a few microseconds. Electrical power supply was provided by VNIIEF, target with diagnostics by CEA.
A liner implosion experiment was conducted on facility Pegasus-2, in which two perturbation type growth was compared. On one half (through height) of the cylindrical liner sinusoidal azimuthally ...symmetric perturbations were produced. On the other liner half the perturbations were of the same wavelength and the same amplitude, but the angle between the wave vector and the cylinder axis was 45/spl deg/ (screw perturbations). The experimental radiographs show that there is essentially no screw perturbation growth, while the azimuthally symmetric perturbations grow many-fold. This result agrees with the theoretical predictions.
A high energy, massive liner experiment, driven by an explosive flux compressor generator, was conducted at VNIIEF firing point, Sarov, on August 22, 1996. We report results of numerical modeling and ...analysis we have performed on the solid liner dynamics of this 4.0 millimeter thick aluminum liner as it was imploded from an initial inner radius of 236 mm onto a central measuring unit (CMU), radius 55 mm. Both one- and two-dimensional MHD calculations have been performed, with emphasis on studies of Rayleigh-Taylor instability in the presence of strength and on liner/glide plane interactions. One-dimensional MHD calculations using the experimental current profile confirm that a peak generator current of 100-105 MA yields radial liner dynamics which are consistent with both glide plane and CMU impact diagnostics. These calculations indicate that the liner reached velocities of 6.9-7.5 km/s before CMU impact. Kinetic energy of the liner, integrated across its radial cross-section, is between 18-22 MJ. Since the initial goal was to accelerate the liner to at least 20 MJ, these calculations are consistent with overall success. Two-dimensional MHD calculations were employed for more detailed comparisons with the measured data set. The complete data set consisted of over 250 separate probe traces. From these data and from their correlation with the MHD calculations, we can conclude that the liner deviated from simple cylindrical shape during its implosion. Two-dimensional calculations have clarified our understanding of the mechanisms responsible for these deformations.
High power pulsed energy sources are required to produce a large amount of X-rays. The leading role in creation of ultra-high power stationary machines belongs to the USA national laboratories. ...VNIIEF has made much progress in creation of ultra-high power explosive magnetic generators (EMG) of a single action, which allow experiments up to 200 MJ of the stored energy and up to 10/sup 13/ W of the power in the load.
Study of high-energy liner compression in HEL-1 experiment Chernyshev, V.K.; Mokhov, V.N.; Buzin, V.N. ...
Digest of Technical Papers. 11th IEEE International Pulsed Power Conference (Cat. No.97CH36127),
1997, Volume:
1
Conference Proceeding
The paper describes arrangement and the results of the first joint experiment between VNIIEF and LANL with explosive magnetic generators (EMG) of 1 m diameter and a nonevaporating liner. The ...experiment took place in August 22, 1996. The goal of the experiment was to accelerate magnetically cylindrical relatively thin aluminum liner and to get kinetic energy of 20 MJ or more. As the energy source for the experimental device we chose 5-module DEMG of 1000 mm diameter, tested many times in the experiments for rigid and liner loads. This EMG can store more energy than any other EMG created at VNIIEF. The physical scene of the liner unit was chosen so that the growth of disturbances would have less influence on the liner shape during flight, especially on the liner's inner surface. The shape of glade plane on which the liner slides during flight and the way of contact liner with walls were chosen on the grounds of 2-D calculations, proceeding from the necessity to ensure electrical contact during the liner flight.
Relatively soft X-rays (quantum energy about 0.3 keV) may be produced by acceleration of a plasma liner up to a velocity of /spl sim/300 km/s followed by stagnation in a pinch. This means that if the ...plasma acceleration distance is several cm, the time of plasma motion must be about 0.1 of a microsecond. This results in a difficulty, associated with the problem of plasma stability and the liner having very small thickness and very small tolerance on initial thickness and density. Besides, quick energy input into the load requires complicated fast opening switches, which need to be experimentally tested. For experiments with explosive magnetic generators (EMG) it is reasonable to develop simpler systems to reach mass velocities about 300 km/sec. The work by A.M Buyko et al. (1995) theoretically considers one of these systems, where a liner mass during its magnetic deceleration significantly decreases and the velocity increases, i.e., a variable mass liner (VML). The same work suggests two experimental designs to test a new concept: full-scale experiment, including X-rays generation and a model experiment, including testing of the initial stage of VML formation (v<l00 km/sec). This paper describes the first model experiment designed to test the VML concept proposed by VNIIEF to produce soft X-rays with the megajoule energy level (joint experiment "X-Ray-1" between Russia, and the USA, 1995, VNIIEF).
The imploding liner is a cylinder of conducting material through which a current is passed in the longitudinal direction. Interaction of the current with its own magnetic field causes the liner to ...implode. In August, 1996, a high energy liner experiment (HEL-1) was conducted at the All-Russia Scientific Research Institute (VNIIEF) in Sarov, Russia. A 5 tier 1 meter diameter explosive disk generator provided electrical energy to drive a 48 cm outside diameter, 4 mm thick, aluminum alloy liner having a mass of about 1 kg onto an 11 cm diameter diagnostic package. The purpose of the experiment was to measure performance of the explosive pulse power generator and the heavy imploding liner. Electrical performance diagnostics included inductive (B-dot) probes, Faraday rotation current measurement, Rogowski total current measurement, and voltage probes, flux loss and conductor motion diagnostics included current-joint voltage measurements and motion sensing contact pins. Optical and electrical impact pins, inductive (B-dot) probes, manganin pressure probes, and continuously recording resistance probes in the central measuring unit (CMU) and piezo and manganin pressure probes, optical beam breakers, and inductive probes located in the glide planes were used as liner symmetry and velocity diagnostics. Preliminary analysis of the data indicate that a peak current of more than 100 MA was attained and the liner velocity was between 6.7 km/sec and 7.5 km/sec. Liner kinetic energy was between 22 MJ and 35 MJ.
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