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Submitted on 1 Jan 1979
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REMARKS ON THE BREAKDOWN OF AN ELECTRIC GAS DISCHARGE
D. Grosu, C. Grosu
To cite this version:
D. Grosu, C. Grosu. REMARKS ON THE BREAKDOWN OF AN ELECTRIC GAS DISCHARGE.
Journal de Physique Colloques, 1979, 40 (C7), pp.C7-181-C7-182. �10.1051/jphyscol:1979789�. �jpa- 00219495�
JOURNAL DE PHYSIQUE CoZZoque C7, suppldrnent a u n07, Tome 40, J u i Z Z e t 1979, v a g e C7- 181
REMARKS ON THE BREAKDOWN OF AN U-ECTm GAS DECHARGE
D. Grosu and C.S. Grosu.
FacuZty o f P h y s i c s , J a s s y , Romania.
While perforning our experimental s t u ~ dy on the influenae of the nsture of the tube WalL u p o ~ the breakdown of an eleo- t r i e disoharge
p]
we notioed, i n eome eases, the presanoe of two minima instead of one on the Paschen ourve. The Pasohen ourveer were obtained in the nitrogea,pre- pared by hea4ing BISNa,ln a dieoharge tube l i k e the one Pn F&g.Pa w h l ~ h we aalled a double wall %ube (DWT) o r a double tube(DT). The (DWT) o w e @ a r e regreseated ia Fig.2: by dots, as foaotiorn of preasum, the values of the breakdown potentials,
Pig.1 Fig. 2
and by oirelee, %he mluee of
the extenotion potentials. We goticle the presrenae o f twa miw.The lower preeeu- r e minimum i e ovry pointed a3ad the &if%
E m m 4hie echimura t~ Che maximtm i e aehi- eved by a lowelFSag of the pre;ereare with 0.02 Tern at the The twe otmrvee goin tioge,her in the large sr art
Sower preaamre, w h e ~ the disarharge i e intenmitent, We put aside the D2 dime-
t e r tube
-
Erig,lb and raised again the Pasahen atzrve. We also ~ ~ p r e 8 e n t e d 3.n Fig-2 the value^ 02 the breakdown a a d er- tenetion potentials Pn a single tube (S.T) The o a y m i n i m u m of t h i s alzrve oacurs st the sac preaeure where the p o u t e d minl- mwn i n tho ( D W ) oaee occurs. We obtained 8 i m U s E reeults by replaaing the eleotmde with Do = 24 6Sl by a 16 BUU one W d the glass tabs of D2 = 26 mm by 8n 18 mm om.p(Torr)
''01
' 620- dm' 660'dad ibo' ibo'
i i o t I ~ O 'Fig. 3
t e , the elecrtim~dea were of A 1 wi%B a &St#-
Oanare of 12 am between *em.
We -took f@r -tea *ha$ *he walle of
Phe two tubes 3afluenae %he b ~ ~ e l r d s m bg p o l a r t z i ~ the dielea*qio $n the e l e u t f i a
f i e l d betweea the electrsdee. TWQ aerie6 of experiments were pergowed h pnzve e- ELE h y ~ ~ t h e e i ~
I n the fin% st~ries,.we i n 0 ~ d u a e 8 &A-
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1979789
e l e o r t i o liquid81 with a r e l a t i v e prrmiti- v i t y h i g h n them with g l a s s (Pyrex,
Er -
3.6). between the two w a l l s of t h e tube i n hig.3.
I n the abeenee of t h e l i q u i d , with a i r between the walls, we obCained the eurves i n big.3, With water and aaetone
7 with
(CH3.C0.CH3) we got r e s u l t s simile-ryfhoee of nitro-methane (PJ0$.CH3) whicrh we re- presented in FIg.4. By comparingC these ourves with ones i n Fig.3 one noticee an influenoe of t h e d i e l e o t r i o l i q u i d upon
t h e values of t h e breakdown p o t e n t i a l s , whioh it r i a e s obviotasly within t h e pree- s u r e range (0.20
-
0.50) Torr. Then the minimum f o r higher pressures becomes more pointed and t h e breakdown is more d i f f i - oult!, The lower presetares minimum is not influenced. A speoial ease i e represented by nitro-benaene (C6H5.102) i n the pre- senas of whieh t h e l a r g e m i n i m as lon- g e r soears. A g r e a t number of determina- t i o n s wamr made f o r eaah l i q u i d , but t h e r e s u l t s remined the same*We obtained similar r e s u l t s by repla- oing gp w&$h U 11n the Ne case t h e bre- akdown is e a s i e r and t h e minims are l a r -
ger. The passage from t h e maximum t o the more pointed minimum i s asso aahieved f o r a decrease of the pressure by 0.02 Torr a t the most; i n the l e caee t h e r e is a l s o onay one minimum in t h e presenae of n i t r o - beneena.
We used a simple tube (ST), l i k e the ones in Fig.lb f o r the second s e r i e s of experiments. With a tube of dhe same di- mensions a s those of the one i n t h e mid- d l e of Fig.3 we got r e ~ u l t s s i m i l a r t o thoee in Fig.3. With a tube of the same dimensions as thoee of t h e i m e r one i n Fig.3, but De
,
34 mm, w e obtained the Paschen curve with only one ~ninimum. Fin- naly, f o r an fntenaediate tube, Dl = 26 mm and De = 24 mm we obtained a two mini- m a curve, bat t h e pafentiax differenoe between t h e maxfolusl and the minimum bre-akdown p o t e n t i a l s was only (20
-
30) 8 .We r a i s e d the: Psschen curves as well as those of the extenction p o t e n t i a l s i n
%he O2 case, too, prepared by heating p o t a e i u pennangonate. Only oae minlmura was notioed in a11 eases.
The main r e s u l t s of' our inveetigaPione a r e 1
1. The revealing of the two minlma Paschen ourve i n t h e aase of an e l e c t r i o dieoharge breakdown i n N2 and He;
2. The discharge breakdown i s a l s o iniluenoed by phenomem a t t h e tube wall.
REFErnNCES
1. D.Grosu, St.Bara and C. Bruras
-
X L I I - t h ICPIQ, Contributed papera, part.1, 357, DDR, Berlin (1977).
