Selective Excitation Processes in Gas Discharges

The electron swarm development in nitrogen is studied for E/N values from 56.6 to 1131 Td by a Boltzmann equation method in which the effect of ionisation is considered properly. Alteration of the electron collision cross-sections from the literature is limited to a minimum, although minor amendments are found necessary for the ionisation coefficient to agree well with previous measurements. The cross-sections for vibrational excitation are considered separately for its quantum number v=1-10. The electron swarm parameters are calculated for the time-of-flight, pulsed Townsend and steady-state Townsend experiments. The results show that the deduced electron drift velocity, diffusion coefficient and mean energy are generally in good agreement with previous experimental and theoretical values.

Section: 2 Ionisation Ri Excitation Rex and Momentum Transfer Collis...mentioning

confidence: 84%

Boltzmann equation analysis of the electron swarm development in nitrogen

Taniguchi

Tagashira

Sakai

1978

“…The dependence of the ratio I 7032 /I 6678 on pd in T 2 and T 3 is shown as the curves 3 and 4 in figure 5. In order to compare with the theoretical calculation, the dependence of T e on pd can be obtained by using the formula to calculate the electron temperature in a circular discharge tube [11], which is also shown as the curve 5 in figure 5. From figure 5, it is evident that the ratio I 7032 /I 6678 of spectrum intensity is dependent on pd and so is electron temperature T e , even if their diameter d is different.…”

Section: Validation Of Diagnosis Methodsmentioning

confidence: 99%

“…where N m is the production rate of the population in the upper level m. A mq , v mq are the Einstein coefficient and the frequency of transition from m to q, respectively, and h is the Planck constant. Assume the population in the upper level m is directly excited by electron collision, then [11]…”

Section: Principle Of Diagnosismentioning

confidence: 99%

See 1 more Smart Citation

Probe-spectrometry diagnosis of electron temperature in narrow discharge plasma at low pressure

Ling¹

2006

A new technique, the two-stage probe-spectroscopic diagnosis method, is proposed to diagnose indirectly the electron temperature in a narrow discharge plasma at low/middle pressure. The first stage includes the diagnosis of electron temperature Te by the double probe method and measurement of the emission spectrum in an ancillary discharge tube. From its emission spectrum, a pair of spectral lines is selected in such a way that the ratio Imq/Inr of their intensities, Imq and Inr, is changed monotonically with gas pressure. The corresponding relation between the electron temperature Te and the ratio Imq/Inr can be obtained in the ancillary discharge tube at certain pressure. During the second stage, the electron temperature in the diagnosed discharge plasma can be determined from its ratio Imq/Inr according to the above relation between Te and Imq/Inr obtained in the ancillary discharge tube. As an example, the electron temperature in a high power flat He–Ne laser is diagnosed using this probe-spectrometry diagnosis technique. The experiments prove that the calculated electron temperature is obviously higher than the actual electron temperature in the low pressure or small size discharge. The principle, method, setup and results of this diagnostic technique are discussed in this paper.

“…In order to compare the experimental results with the theory the following discharge parameters were substituted into (18). Temperature of electrons (included in D a ) was taken from [25], E/p values were those published in [26] and [27] for helium and neon, respectively. Einstein relation µ + /D + = e/kT g was assumed to be valid in the investigated range of electric fields.…”

Section: The Exponential Decaymentioning

confidence: 99%

Cathaphoretic confinement of Zn evaporated into helium and neon discharges

Bánó

Horváth

Rózsa

2000

Cathaphoresis of Zn evaporated into the positive column of helium and neon discharges was investigated both experimentally and theoretically. The side-light intensity of the Zn-I 518.2 nm transition was recorded along a 4.5 cm long positive column discharge with an inner diameter of 3 mm. The buffer gas pressure was varied between 10 and 25 mbar while discharge currents of 20-60 mA were applied to the tube. Reasonably good agreement was found between the experimental data and the theoretically predicted axial distribution of zinc concentration in the tube. The results can be useful in the design of the cathaphoretic confinement section of the different He-Zn laser tubes and a prospective Ne-Zn laser system, which would operate in the deep ultraviolet region (210 nm).