SU311568A1 - LIBRARY - Google Patents

Description

The invention relates to devices containing a number of synchronously applied gaps and used, for example, in high-voltage impulse technology.

Blocks of controlled arrays, in particular, with a gaseous dielectric, are known that are triggered by a beam of an optical quantum generator — a laser. The laser flux is directed either to one of the glitter electrodes or focused into one of the points in the interelectrode space. As a result of the interaction of laser radiation with the substance of the electrode (photoemission, rapid evaporation of the surface layer of the electrode, etc.) or with the dielectric gap of the working gap of the discharge, the initialization of the breakdown occurs in the gap to which a voltage is applied.

In modern pulsed technology, it is often necessary to synchronously switch a number of electrical circuits using spark gaps as switches. Such schemes include simultaneous switching of independent drives to separate or total load, such as, for example, in a combined pulse voltage and current generator, in pulse current generators, where several connectors are switched into a parallel circuit, in pulse voltage generators, Arkadyev- Marx, in generators with multiplication of voltage on noloscopic lines, coaxial cable, etc.

The triggering of arresters in such circuits with the help of laser radiation has great advantages, since the laser beam allows isolation of the main circuit from the triggering device by voltage, which is very significant in high-voltage impulse technology.

Nowadays, to simultaneously start several discharge gaps by a l.-grain beam, it is separated by optical means. on: 1rl er multifaceted features, mirrors dissected into lnzamn.

The disadvantages of this type of device include the complexity of the G system and the greater complexity of its adjustment; crpoiiKH for each gap, as well as radiation tolerances on the reflecting and grounding surfaces of the optical system.

The proposed unit to equilibrate the distribution of laser radiation over switched gaps does not increase the reliability of the system, and the gaps due to more efficient use of the radiation energy. It is limited by the fact that the cross section of the ray of the beam.: I; i:, the epa is separated by successively cutting off its parts by light absorbing elements, lianpuMep targets or screens, which are parts of the working electrodes, in a particular case by emitting radiation in wheel-shaped areas of the system diaphragms with gradually decreasing openings.

Let us consider the mechanism of breakdown of the spark gap under the influence of a laser: 0 () radiation. If the emittance; ia3epHoio of radiation exceeds some 1 of ij, then the main process is the evaporation of the material of the electrodes, and

.r „.3 ..-- 1, (1)

where Q is the heat of evaporation of the electrode material;

PO is the density of the electrode material; b - material thermal diffusivity;

t is the duration of the laser pulse.

Therefore, the main factor driving the gap to breakdowns must be electron emission — from electroschugs. The rapid evaporation of the surface layer of the electrodes leads to the creation of a shock wave to the gas, and consequently to a redistribution of the gas density in the gap, which increases the coefficient of the unit ionization in the shoals: the area of the inter electrode space and the breakdown of the projectile gap. The critical flux density for the co-critical case, sodium copper electrode electrodes ;;, about 1000 MW-cm. As can be seen, the critical radiation density is quite significant, although attainable at the modern level of development of lasers. However, to obtain such densities as a supporter, because significant thermoelectronic emission from the electrodes occurs already at a temperature close to the melting point of the material. Since the absorption depth of the radiation in the metal is cm, the mass of the substance at the copper electrodes is r-sl2. To heat it to a melting temperature of 1100 ° C, a radiation density of about 0Г-С.1Г is required. Modern quantum generators operating in the Q-switching mode make it possible to obtain such a density of radiation even without focusing devices. Indeed, for example, for a ruby laser e with a beam of dzga. Metro.m 10 mm and a monodality of radiation of 20 mt, the density of radiation is 26 m-cm--.

It is advisable to distribute the laser radiation flux evenly over all the gaps, in the particular case, in the form of discs with holes the diameters of which are narrowed in the direction of the radiation. The dependence of the diameter of the electrodes of the electrodes on the no. Meter p ;; distribute and; -; cnn is expressed by the following equality: 0l π - (and-) O1. (2)

Here is the DQ-original laser diameter: the 10th beam (since the radiation: 1e is distributed over the beam section 1 heraviomeri: o, weakened along the edges, it is practically possible to use about 80% of the area of the beam);

DI is the diameter of the hole of the first diaphragm (chosen by constructive considerations, i.e., due to practical feasibility of the difference in diameters and

adjusting the electrodes because

the magnitude of the illuminated area does not significantly affect the characteristics of the spark gap breakdown);

n-number of the electrode.

I like the well-borne discharge develops in the form of a narrow caial whose transverse dimensions are significant: the smaller the transverse size of the aperture of the diaphragm, except for the last of the ectrols, and the time of the 11 | By receiving one, the dimensions oTnepcTHii can be chosen from the mustache, cho: h1. Colpillon colnevone area diaphragm: chy, P01: and tsushcheu ray, which is generally not technically sensible;

The value of any prev; 1uzh: 1i at the same time (; .m zaihsku: 1sek sparkle: 5th zazo) OG ,, NOM.M (; CONSTR.

svol1 ts but shchtstest- to precisely their srabaty: ani in nmemeii.

(3)

four

where /; - a piece of pro.mezhutkov;

/ - distance between adjacent

gaps; c is the speed of light.

The condition (3) imposes a restriction on the number of numbers; you can do it: 1 turn, since t-t should not exceed the following requirements: 1 st front edge duration: 1 Hip i.ioi-o: i.upy ijjca.

Pa in the drawing is a schematic illustration ;; a en block of rights.: 1 elp: their discharge: 1 pic; 5, 5 salted for communica luiH independent 11 en: 1.

First seven of eight consecutive

1 x disk drives 1–8:. | Signals ±U are marked once: 1nosity of notennals, applied 1a to the corresponding1, electrode: m, symbols D - bottom. Meters of holes in the diaphragms, and arrows show the flow of laser radiation. Daser radiation is absorbed in an annular area at each even: 1st electrode 2, 4 and 6, as a result of which breakdown of gaps between electrodes / -2, 3-4, 5-6 i-i is initiated.

Subject invention

A block of controlled arresters containing a pulsed laser and a series of arrays arranged in series along the path of the laser beam, characterized in that, in order to increase the efficiency of the use of radiation and the radiation energy, at least one of the electrodes of each of the arrays is supplied

a light-absorbing element whose surface is part of the working surface of the electrode, for example, in the form of diaphragms with successively decreasing holes, the light-absorbing elements being located in the radiation aperture so that their total illuminated area is equal to the cross section of the laser beam.