HAL Id: jpa-00219160
https://hal.archives-ouvertes.fr/jpa-00219160
Submitted on 1 Jan 1979
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
CURRENT VOLTAGE CHARACTERISTICS OF A SELF-SUSTAINED ELECTROPHOTOIONIZED
DISCHARGE IN LASER MIXTURES
E. Glotov, V. Danilychev, A. Milanich, A. Soroka
To cite this version:
E. Glotov, V. Danilychev, A. Milanich, A. Soroka. CURRENT VOLTAGE CHARACTERISTICS OF A SELF-SUSTAINED ELECTROPHOTOIONIZED DISCHARGE IN LASER MIXTURES. Journal de Physique Colloques, 1979, 40 (C7), pp.C7-371-C7-372. �10.1051/jphyscol:19797182�. �jpa-00219160�
JOURNAL DE PHYSIQUE CoZZoque C7, suppZ6ment au n07, Tome 40, JuiZZet 2979, page ~ 7 - 371
CURRENT VOLTAGE CHARACTERISTICS OF A SELF-SUSTAINED ELECTROPHOTOIONIZED DISCHARGE I N LASER MIXTURES
E.P. Glotov, V.A. Danilychev, A.I. Milanich and A.M. Soroka.
Lebedev Physical Insti6ute, U . S. S. R. Academy of Sciences Leninsky prospect 53, 12 7924 Moscow U. S. S . R.
Three-component ocmpressed mixtures of density in the resonator (ca scc-' 2 1; /?a ,
rare-gas (A,R) and haloid molecules (H2) the rate constant for electrolz attachment are one of the most active media for Power- to Hz; ,fie, the constant of electron-ion ful optical gas lasers /I/. In /2/ a self- recombination with AR* molecv.lar ions; hi,
sustained electrophotoionized discharge the constant of ion-ion recombination of (EPI-discharge) has been proposed, and the negative H and positive i d ions; /{t, the calculation for a three-component laser mix-rate constant of molecular ion formation ture Ar:Xe:CC14=1500:50:l at r=2 atm Pre- at triple collisions of 11' and two A atoms;
sented. In the present paper the conditions L, the active region length; andfi,~, the for steady-state burning of a self-sustai- reflection coefficients of the resonator ned EPI discharge in A:R:H2 laser mixtures mirrors, and 6&, the cross section of la- where the quantum energy is sufficient for ser light absorption by I&+ ions. nhen derj photoionization of low metastable levels ving the system (1 ) , the laser signal was of the rare gas (R*) are considered. Cur- asswned to be saturated.
rent-voltage calculation characteristics Por the given optical resonator parame- (cvC) are presented and the conditions for ters and the active region length all stea- discharge stability are found. The reduced dy-state discharge paraineters are defined equation system for $PI-discharge in three by E/P. The correlation between the elec- component laser mixizces at tlle point aP- tron density and the field intensity is
proximation is: given by :
6 ,w ( ~ h r ? ~ - ~ a RE GY@G P/P)~= c Ka%~.p, &iE$+~~d%f* g + ~ @ ~ ~ ~ ~ + t r ~ + ~ + $ 1 3 ~ ~
~ - . 6 ' r % ~ ~ ~ - h ' ~ & f l ~ - A AR**, y - k A % a ~ r ~ a ( i + ~ ~ + p e Q / ~ a ~ z ) - i (2)
$$G a & R * - ~ ~ L X - A C , ~ ~ , ? ; Y= R-(j/~crz)Be (2L &
Figure sho~vs the CVC of the ZPI-discharge
# ' . x ~ A W - J ~ H - A R + - ~ I ~ ~ AR; ,,@+H-= R++A~;
P&=~;&R*+&&/I~ - G(4/fifi&& - 6'; R% -6a ARC.& for different values of the resonator tra- Heree,jy,, are the charge and electron mo-
nsmission. One can see the existence of bility with density ne; d , the part of
the minimum ~/~@/P),~~parameter depending energy spent on A* electron level excita-
on the resonator. Starting from this va- tion with energy &A ; Kr , the rate constant
lue of E/P the steady-state burning of of RH* excimer formation at R* and H2 col-
the self-sustained discharge is possible.
lisions; 6 , the cross-section of photoio-
There are two build-up and drop-dom cur- nisation R*; y@, the laser radiation flux
ves in the EPI-discharge CVC. The elect-
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19797182
without the external resistance in the discharge circuit /3/. One of the CVC cur- ves with different loading lines is pre- sented in Fig.2. As is seen from Big.2, there is a minimum value of external re- sistance for each of the points along drop- down CVC (the loading curve 1 touches CVC at this point) that makes possible the steady-state burning of EPI-discharge.
When ballast resistance i e R r Q, the loa- C7- 372
ron attachment to the haloid molecules is the main mechanism of electron loss on the drop-down curve of CVC. In the case of the build-up curve the process of dissociation
recombination with AR+ molecular ions is do-/,-- minating. Since the growth of miblecular ion density AR+ is not proportional to the gro-,.
nth of ne (due to the finite rate of AR+
formation 'from R+), then starting from some
points. But the only stable crossing point value E/P the electron loss would not com-
is the one corresponding to a smaller E/P pensate the electron origin, and no steady-
value. fix is derived from:
state burning i.s possible. Note that if R+
a- ) 2 - (4)
1,
ion is ins%antly transformed into bRf , then ka 3(fgY)2+i the building-up CVC curve would exist at any
where fi, is the resistance of a discharge value of ED (instabilities connected with
gap; e , the distance between electrodes, a stepwise ionization are not taken into
and S, the electrode area.
account). Thus, the region where the build
The eastence of parasitic capacitance up curve exists is restricted from above
by the following E/P value: C of a discharge gap can make the drop-
C A P
laser operation Eq. ( 5 ) is valid. The
Is-
?$-.
R-•
i3 --
?Z - *
drop-down curve is of intsrest for laser down curve unstab8e even at R 7 R,-/4/.
-
But in the case when &Cp time is much smaller than the typical plasma formation time, the presence of a parasitic capaci- tame does not interfere the stability of discharge burning. Here the acceptable pa- rasitic capacitance is defined by:
3 4
applications since energy loss for photo- I 2
= ~ ~ + m + i & f
.&&, (5) It is drop-dom CVC is unstable Under the conditions typical of excimerioniz'ation is less than for buildup curve.
Stimulating discussions with 0. Kerimov and G. Shapiro are acknowledged.
References
7. V. ~aniljrchev et al.Radi otekh. ,l2,1977.
2.N.Basov et al. .Zh TP Letts.
3. L.Leb. Processes of Electric dischasge in gases, I.-L.,Gostekhizdat,l950.
4. L.Bessonov. Theoretical Grounds of Electrotechnics. ,M., "Vysshaya Shkola"
1978-
