Temperature distributions in a helium plasma

Abstract

Temperature distributions are determined in a helium plasma, the power used being 27 kW and the gas flow rate 7.2 g/minute. Pressure conditions for the plasma under study are respectively 760 and 300 mm Hg. The spectroscopic method used for obtaining temperatures is that of Larenz or the method of maximum emission, applied to the 3,889 Å neutral helium line. A maximum temperature, on the plasma axis, of approximately 24,000° K is obtained.

Thermal Behavior of a Plasma-Heated Tungsten Probe in the Presence of Tungsten Vapor

“…From Eq. [6] to [9] together with the value at hand for nw, one can write [nw(KAr --Kw) --KKAr] n2w+ + 2KwKArnwnw+…”

“…Solving [10] for nw+ (discarding the negative root), the total number of tungsten particles nww can be written nW ~-nw+ = nww [11] From the knowledge of nw and nw+, together with Eq. [6], [7], and [8], a value of nAr should be found which is identical to the assumed one and an iteration method is applied until this requirement is fulfilled. In this way, a final value is obtained for nwT in the plasma gas mixture.…”

“…The plasma gas temperature around the probe is obtained by a spectroscopic method using the intensity emission ratio of argon lines 4158.6A and 4259.4A as described in a previous article (5). The solid surface temperature is recorded by pyrometric observations and the validity of this method, which could be altered by the presence of a continuum emission from argon, has been controlled and found acceptable, using a method described elsewhere (6).…”

“…Saha constant at temperature T for the system W---> W+ + e (he) (nw+) Zw+(T) ( 2xmekT ) 3/2 e kT[6] Zw(T)h Saha constant at temperature T for the system Ar --> Ar + Total number of particles at temperature T K = (nAr) + (nAr+) + (nw) + (nw+) + ne =…”