THE PECULIARITIES OF THE DIFFUSION PROCESSES IN THE ELECTRONEGATIVE GAS PLASMA

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THE PECULIARITIES OF THE DIFFUSION PROCESSES IN THE ELECTRONEGATIVE GAS

PLASMA

G. Arutunian, G. Galechian

To cite this version:

G. Arutunian, G. Galechian. THE PECULIARITIES OF THE DIFFUSION PROCESSES IN THE ELECTRONEGATIVE GAS PLASMA. Journal de Physique Colloques, 1979, 40 (C7), pp.C7-205- C7-206. �10.1051/jphyscol:19797101�. �jpa-00219071�

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JOURNAL DE PHYSIQUE CoZZoque C7, suppl6ment au n07, Tome 40, JuiZZet 1979, page C7- 205

THE PECULIARITIES OFITHE DIFFUSION PROCESSES IN THE ELECTRONEGATIVE GAS PLASMA

G.G: Arutunian, G.A. Galechian.

Jerevari State University, Research I n s t i t u t e of the Condensed mediwn Physics.

The dependence of t h e ambipolar d i f - f u s i o n c o e f f i c i e n t s of t h e charged p a r t i c - l e s :D

,

^D: ^and^D? i n t h e e l e c t r o n e g a t i v e gas discharges on

d =k/fle

(Yl-,

ne

^{w e}

n e g a t i v e i o n and e l e c t r o n c o n c e n t r a t i o n s ) a r e considered i n [l]

- ^I33 .

^{It i s}t u r n e d o u t i n

14

^{t h a t}^:^D has o n l y p o s i t i v e va- l u e s and s l i g h t l y changes by exchange

d

from till 10'~. But i t is shown i n [2] t h a t :D i s n e g a t i v e and t h e

n,

^flow

i n t h e c y l i n d r i c p o s i t i v e column i s direc- t e d from t h e walls of t h e t u b e t o i t s axis.

T h i s paper s t a t e s t - i a t depending on t h e c o n d i t i o n s i n t h e discharge :D m y be n e g a t i v e , p o s i t i v e o r e q u a l t o zero. Besi- des, when

DS

(0, t h e n e g a t i v e i o n flow can be d i r e c t e d b o t h from t h e plasina column a x i s and t h e appositive d i r e c t i o n

(depending on t h e d i r e c t i o n o f t h e n,-gra- d i e n t ) a s i t i s known t h a t t h e n,-distri-

b u t i o n along t h e r a d i u s may be b o t h para- b o l i c

( \ m , < O

⁾and two-humped ,63

(

Vn,>O

i n t h e n e a r a x i s r e g i o n ) . The d i f f u s i o n flow o f charges i n s t a e o n a r y e l e c t r o n e g a t i v e gas plasma i s w r i t t e n a s follows :

= - v n

( 1

II =- avn--pan- ^E7

¹²¹

=-Devne-penr E*

^{( 3}1

Where

r

^{i s}t h e p a r t i c l e flow d e n s i t y ;

M

8

i s t h e m o b i l i t g ;

Ect

i s charge s e l f consis- t e n t f i e l d ; D i s d i f f u s i o n .

L e t ' s take

Y=G/'=&/T++'&/T~.

^The

c o n d i t i o n s of t h e flow ~ u a s i n e u t r a l i t y and e q u a l i t y a r e w r i t t e n as follows:

n+=n,+n,

T+=T-+& ^; n+V+= n-K+ncve

Having i n view t h a t D+ 3 D- from (1 )-(3 ) we o b t a i n :

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19797101

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i n c a s e 4) 1 0 , V,M, 2

g

= ^V+p+.

^From

Where

&(o)

i s t h e ambipolar f i e l d w i t h

d=O .

From t h e diagrams of F i g . 1 i t f o l l o w s t h a t t h e r a t i o

E + ( ~ ) / E % (0)

i n t h e i n t e r v a l

fF3 6 d< If 10

i s e q u a l t o 1, and f o r 1 + 1 0 s d ~ 1 . 0 ~ + 1 0 4 t h i s r a t i o s h a r p l y d e c r e a s e d and t e n d s t o z e r o . The ambipolar d i f f u s i o n f i e l d pers t u r b a t i o n i n c r e a s e s w i t h t h e r i s e of E/P w i t h i n t h e i n t e r v a l 1 t 1 0 & 0 ( ~ 1 0 ~

+ l o 4

f o r t h e g i v e n O(

.

F o r B o l t m a n n d i s t r i - b u t i o n of i o n c o n c e n t r a t i o n i n t h e d i - s c h a r g e ( o b t a i n e d e x p e r i m e n t a l l y i n [1] ) one may w r i t e :

vn-d d on,

d+d

From t h e c o n d i t i o n s ' o f t h e ' q u a s i n e u t r a l i - t y and f l o w e q u a l i t y , (1)-(6), we o b t a i n f o r t h e i o n f l o w mean v e l o c i t i e s :

Fig.2 shows t h e diagrams of v;/V+ f o r d i f f e r e n t # d e p e n d e n t on

d

a n d c a l c u l a t e d a c c o r d i n g t o t h e ( 7 ) . The c u r v e s o f f i g . 1 and f i g . 2 a r e c a l c u l a t e d f o r oxigen. From t h e s e diagrams i t f o l l o w s : 1 ) V-/V+ = 0 , when

d=do

; 2 ) V - P + 4 0, when d<dr,

i . e .

n,-

flow i s d i r e c t e d , t o t h e p o s i t i - v e column a x i s ; 3 ) V_/V+

+

^{0, when}O ( > O ( ~ , i . e . n - f l o w i s d i r e c t e d t o t h e t u b e ' s w a l l . F o r d > 1 0 and 8 = 3 0 , v _ / V ? ~ and

fo-'

io* fO" 1 !Of 10' 10' f0 * d

Fig. 3

( 1 ) - / 3 ) . ( 6 ) we o b t a i n :

0 :

' '

'

Fig.3 shows D:/D+,

D:/D+

dependent on O( ; t h e c a s e

E/P

= 4 0 d r ( q c o r r e s ~ o n d t o t h e c u r v e s 1 , 4 ; E / P m

30

v/un.to?-to t h e c u r v e s 2.5;

~/pt20Y/W).tox-

^{t o}t h e c u r v e s 3 . 6 - Fig.4 shows t h e dependences o f D:/D+ and D!/D+ on

d

^;t h e c a e e

E / ~ = 4 0 ~ m t o ?

c or-

.,respond t o th. c u r v e s

~ , ~ ; E / P ~ ~ o ~ w . ~ o ? -

t o t h e c u r v e s 2 , 5 ; ~ / p ~ 2 0 v / c r n - t ~

-

^{t o}

t h e c u r v e s 3,4. For O ( & 0 , 4 , :D = De a

,

l i k e a d i s c h a r g e i n t h e e l e c t r o ~ o s i t i v e

gases References

1. Thompson JOB. ,Proc.Phys. Soc. ,=,8l8 (1959)o

20 Sabadil H. ,Beitr.Plasmaphys. ,ll,53(1971:

3. ^Arutunian^G.G. ,Galechian G.A., J.T.Phys 631 (1978).

4. GGterschulee B ,Zs.f .Phys.2,724 (19%

5. Smith De,Goodall C.Vo, Adams H.G., JoPhyS. Dt Appl*Phy~.,7,194LC (1974).

6. Galechian GOB*, IZVSAB Azm~SSR,Physics,

11,

395 (1976).