TURBULENT PLASMA IN THE FIELD OF INTENSE HIGH FREQUENCY RADIATION

HAL Id: jpa-00219284

https://hal.archives-ouvertes.fr/jpa-00219284

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.

TURBULENT PLASMA IN THE FIELD OF INTENSE HIGH FREQUENCY RADIATION

V. Kovalev, V. Pustovalov, A. Romanov, Vivien Stefan

To cite this version:

V. Kovalev, V. Pustovalov, A. Romanov, Vivien Stefan. TURBULENT PLASMA IN THE FIELD

OF INTENSE HIGH FREQUENCY RADIATION. Journal de Physique Colloques, 1979, 40 (C7),

pp.C7-609-C7-610. �10.1051/jphyscol:19797295�. �jpa-00219284�

JOURNAL DE PHYSIQUE Cozloque C7, stcppt6ment au n07, Tome 40, JuiZZet 1979, page C7- 609

TURBULENT PLASMA IN mE FIELD OF INTENSE MGM FREQUENCY RADIATION

V.F. Kovalev, V.V. Pustovalov, A.B. Romanov and V. stefanx.

P. N. Lebedev PhysicaZ I n s t i t u t e o f Academy o f Sciences o f t h e U.S. S. R., Moscow, U.S.S. R.

Boris Kidric I n s t i t u t e o f Nuclear Sciences, Beograd Yugos Zavia.

In present-day experiments dealing with the interaction of strong electromagnetic radiation vith plasma high energy fluxes of the incident radiation are in use. For exa- mple, in the optical domain of frequencies the energy flux reaches the value of 1016- 1017 W/cm 2 / I / . Along with this, situations when strong radiation propagates through the plasma with high level of turbulent no- ise are very often encountered (plasma fo- cus /2,3/ or ionospheric plasma / 4 / ) . In the presence of the pump field turbulent plasma spectrum is affected in such a way that "failures" appear in the longwave do- main when the wavelenth is of the order of electron oscilation amplitude in the exter- nal field.

For the desciption of the homogeneous i- sotropic plasma interacting with the exter- nal radiation Eo(t)=Eosin wot with the fre- quency wo much higher than the electron Langmuir frequency wLe, Vlasov kinetic equ- ation, in the form of the hydrodynamical system /5/, is used, onthe base of which a nonlinear dispersion relation for the co-

* ^p

²

rreation function

Y '

^{can be}

obtained

Here Jo(xA is Bessel function,

6&(.(2

^par-

u w

tial plasma polarizability of

d

^plasma

component and

&(

and &?)first and second nonlinear dielectric permeahility of

2''

plasma component.

In equation (1) the first addendum inclu- des the effect of high-frequency field Eo(t) on plasma dielectric permeahility

EO(h)

/ 6 , 7 /

the change of nonlinear interaction of pla- sma waves in the presence of the high-fre- queney field is included in remaining adde- nds.

Let us consider now the process of indu- ced scatterinq of the Langmuir waves on par- ticles in the external field Eo(t)when

~*kk,d>>~h~:&dy~

is satisfied. For

I - r

the spectral density of oscillation energy

X ( k ) the following equation is obtained

In a magnetized plasma, the turbulence

-

of the oblique Lanqmuir waves, excited, for example, by encountering electron beams

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19797295

with velocities ti??, paralel to magnetic field Bo is characterized by stationary

+

spectral distribution /4/ which in a strong high-frequency field a=(kt )>1 appeared to 4+

e

he modulated over the frequency with the

2

period

~ * n = d ~

~ b / e ~ .

N

FIere S(

(case\)

describes angle distributions of plasma turbulent noise in the presence of the external field Eo(t). The characte-

+

ristic modulation of the spectral distribu- tion (M: (a) ) connected with the effective amplification of nonlinear interaction of waves in a stronq high frequency field, a- pnears in the form of kernel modification

(QCE,~~,,

^.v

s.'(.r) )

^*

Spectral distribution (3) also describes the modulation of the plasma noise in the case when instabilities arise because of the presence of electron beams in the cu- rrent-carrying plasma with velocity ub (ve- locity of a beam is oriented along drift

-+

^-b*

velocity u, (uub)>O. The angle distribu- tion of plasma noise in that case, certain- ly, has other form /8/. Let us note that modulation of plasma noise by high-frequen- cy external field appears if intensity of

w e L

external field is strong enouc~h

go* -

_{e k}

So, in the above case of current carrying plasma with electron beam defined by para- aeters ne=1~18cm-3, nb/ne=10 -3

,

^{ub=4, 2.10 9}

cm/s, u=4.10 cm/s, Te=Ti=Tb=lOO keV charac- 7

4 -1

with wave number k-2 10 cm could he ex- cited. Here nb

-

particle density of beam electrons, ne

-

particle density of curr- ent carrying plasma electrons, TeIi tem-

~erature of electrons (ions) of current carrying plasma and Tb temperature of beam electrons. In the case of using C02 laser as source of high-frequency field, necessa- ry value of energy flux is q r 4 * 1 0 ~ ~ ~ / c r n ~ : obtainable in present time devices.

REFEREI\!CES

/1/ W.L.Kruer, et al, Collective hehaviour in recent laser-plasma experiments, Lawren:

ce Livermore Laboratory, June 7,Preprint UCRL 777 30, (4976)

/2/ V.A.Gribkov, et al, Works of FIAN,85, (1976) 193,

/3/ K.Yoneyoshi, et al, J.Phys.Jap.g(l976) 1081

/4/ Yu.V.Golikov, et a1,JETP Lett.22 (1975) 3 (in russian)

/ 5 / V.V.Pustovalov, et a1,Lebedev Institu

te Report, No.12, (1976) 28,

/6/ Yu.lY.Aliev, V.P.Silin, JETP 48(1965) 901

/7/ V.I.Domrin, Preprint FIAN USSR, No.38, (1367)

/8/ V.V.Pustovalov, et a17 Preprint FIAN

t?SSR, No. 183, (1973)

teristical for plasma focus, oscilat,%ons with wave number