Vol.3, No 1, 2004 pp. 1 - 6
UDC 533.92
WIEDEMANN-FRANZ RATIO IN PLASMAS
 IN THE MIXTURES OF XENON, ARGON AND CAESIUM
N. V. Novaković1, S. M. Stojilković2, D. Ž. Gajić1
1Faculty of Sciences and Mathematics, P.O.Box 224, Niš, Serbia,
2Faculty of Electronics, University of Niš, P.O.Box 73, Serbia
Abstract. In the present paper, the xenon plasmas containing argon and caesium as additive and pertaining to the above mentioned type (high-pressure, low-temperature, LTE) are studied, and a theoretical evaluation of their basic transport parameters is presented. The numerical calculations were based on the assumption that the system is kept under constant pressure and temperature and that it attained local thermodynamical equilibrium. Some results of a theoretical study which embraced numerical evaluations of the plasma composition, electron collision frequency, electrical and thermal conductivities and Wiedemann-Franz ratio, all regarded as functions of pressure and temperature, are given for high-pressure (from 0,1 MPa to 1,5 MPa) and low-temperature (from 2 000 K to 20 000 K). A previously derived modified expression for the Debye radius, offering the possibility to treat the plasmas considered as weakly non-ideal in the whole temperature range of interest, is used in the evaluations, in combination with the Saha equations for the relevant ionization stages of xenon, argon and caesium.
Key words: xenon plasma, argon, caesium, local thermodynamical equilibrium, number density, collision frequency, electrical conductivity,
thermal conductivity, Wiedemann-Franz ratio.
WIEDEMANN-FRANZ -OV ODNOS U PLAZMI SMEŠE KSENONA, ARGONA I CEZIJUMA
Dati su rezultati izračunavanja osnovnih transportnih parametara u plazmi ksenona sa dodatkom argona i cezijuma. Numerička izračunavanja se zasnivaju na činjenici da je sistem na konstantnom pritisku i konstantnoj temperaturi u stanju lokalne termodinamičke ravnoteže. Dati su neki rezultati o ravnotežnom sastavu, kolizionoj frekvenci, električnoj i toplotnoj provodljivosti i Wiedemann-Franz-ovom odnosu za visoke pritiske (0,1 Mpa –1,5 MPa) i za niske temperature (2 000 K - 20 000 K). Korišćen je izraz za modifikovan Debye-ev radijus, čime je zadovoljen uslov slabe neidealnosti u ukupnom temperaturnom intervalu, u kombinaciji sa Saha-ovim jednačinama za odgovarajuća jonizaciona stanja ksenona, argona i cezijuma.