CHARACTERISTICS OF THE COMBINED DISHARGE IN AVERAGE PRESSURE GAS

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Submitted on 1 Jan 1979

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CHARACTERISTICS OF THE COMBINED DISHARGE IN AVERAGE PRESSURE GAS

Yu. Bichkov, V. Osipov, V.A. Telnov

To cite this version:

Yu. Bichkov, V. Osipov, V.A. Telnov. CHARACTERISTICS OF THE COMBINED DISHARGE IN AVERAGE PRESSURE GAS. Journal de Physique Colloques, 1979, 40 (C7), pp.C7-161-C7-162.

�10.1051/jphyscol:1979779�. �jpa-00219485�

JOURUAL DE PHYSIQUE CoZZoque C7, supptdment au n07, Tome 40, JuiZZet 1979, Page C7- 161

CHARACT€RETICS OF JHE COMBINED DIXHARGE lN A W G E PRESSURE GAS

Yu. I. Bichkov, V.V. Osipov, V.A. Telnov.

fie U.S.S.R. Academy o f Sciences, Siberian Branch, the H i g h - m e n t Etectronics I n s t i t u t e , Tomsk.

Creating high-power C02-laeers by a com- bined excitation way that stimulated fur- ther improving of this method and further research of discharge characteristics is perspective [1,2,3,4,]The combination of both the pulse self-maintained and the main semi-self-maintained discharges are used in the combined excitation methode.

The self -maintained discharge is

by a high-voltage short time pulse source to create plasma with an electron density required. The main semi-self-maintain dis- charge requires lower voltage on the elec- trodes. Usually the large inductor being w e d as a decoupling element prohibits shunting of a high voltage pulse circuit by the main discharge source [2,41. The presence of the decoupling elements makes the diecharge characteristics worse. There is our concept in which two high voltage pulse sources are used, their own currents flowing in the opposite direction. It en- abled us to get rid of the decoupling ele- ments and to carry on the energetic data researches of the combine discharge at a high input energy density into nitrogen of an average pressure, The circuit scheme of this device is shown in fig. 1.

A mesh was deposited into the gas gap made up with two xmin round electrodes with the diameter of 12 cm and with a distance of 5 cm between them. A chsllged 2 uFd capacitor Co was connected afth the main electrodes, it being charged up to Uo that was chosen less than the stai tic breakdown voltage for the given gap.

High-voltage pulses were supplied to the mesh by closing of the commutator K

,

each capacitor C1 and C2 (C1=C2) being discharged into the gap mesh-anode and mesh-cathode relatively producing plasm with a required electron density. The do- minant amount of ePtrQ9 is put into the gas by means of a discharge capacitor

co

in a regime of semi-self-maintained die- charge. A spark gap as well as thyratron were w e d as a connrmtator.

UI

--- ^mesh

Fig. 1

Fig. 2

pig, 2 shone the input energy density by the main discharge into nitrogen as a M o t i o n of the pressure at various values of the E/P. The pressure range P 10.05

-

-

Pcmfl

tom-' high input energy densities Bo=

0.2

-

put by the pulse self-maintained diecharge P waa lees than 10 percent of that put by

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1979779

the main discharge. The fig. 3 shorn the dependence of the energy density put by the semi-self-maintained discharge Eo at various values of E/p as a function of the density energy put by the self-main- tained discharge E,

.

Pig. 3

Thus, the pulse self-maintained discharge using a negligible amount of energy creat- es the plasma with an electron density required. The time of the discharge con- traction appearance as a function of the energy density E, is shown in fig. 4.

E,

The electron density *New created by the pulse self-maintained discharge as a func- tion of El is represented here as well.

Since the-gas flow in gaps is missed in the present researches the discharge con- traction was sure to occur at high energy densities put by the main discharge. The time ,t, as a function of El indicates the high discharge stability. Really, at El= 0.025~rn-~atm~' and E/p = 8.05 V*cm -1 torr-l the energy density in put by the main discharge is Eo= 0.25~crn-~atm-~, here the discharge stability time is tb r

High stability of the discharge an able us to carry on the experiment with the

pulse self-maintained discharge repetitio~

rate *f" = 3,5*10~~.sec-~. The average power density P in put into the main dia- charge and the discharge stability time t, a8 a function of E/p are shown in fig.

5. At E/p = 8 V - cm-hiorr-' the average power density put by the main discharge reaches P = 36 W - C ~ - ~ , here the discharge stability time is ts = 6 ~ o - ~ s .

p

=a.

-

20 f0 ^-

3 4 5 6 7 8

Fig. 5 E/p,

V.

References:

1 J.P.Reilly, J. Appl, Phys., 1972,43, M 8, 3411-3416,

2 A.E.Hi.11, Appl. Phys. Lett., 1973,22, N 15 9 670-673.

3 N.A.Generalov, V.P.Zimakov et al.

Physics plasma, 1977, t 3, v-3,626- 633

4

Lett., 1978, 32, N 7, 418-420.