74 nm Radiative Efficiency of a DC Neon Glow Discharge

The diffuse column of a dc glow discharge in neon is a typical example of a plasma whose properties are mainly determined by the non-local non-equilibrium kinetics of the electron component. Consequently, the space-charge confinement causes a spatial variation of all plasma properties. The effects on the power balance, the ionization budget and the radiation efficiency of a cylindrical column plasma are studied by a detailed self-consistent column model based on a hybrid method. The analysis deals with the impact of discharge parameter variations over larger ranges, of an admixture of a molecular gas as well as of the superposition of a longitudinal magnetic field on the spatial plasma structure. Among others, the non-local properties of the electron power balance and their influence on the radiation efficiency are discussed. The largest influence of energy transport processes on the electron power balance has been observed in a range of the pressure times radius values from about 200 to 400 Pa cm, which nearly coincides with the range where the maximum efficiency of the resonance radiation occurs.

Section: Self-consistent Column Plasma Modelmentioning

confidence: 93%

Power balance and space-charge confinement in a neon dc column plasma

Uhrlandt

2002

“…The temperature of absorbing particles, as well as their radial density profile, is measured. First results have already been described in [13].…”

Section: Introductionmentioning

confidence: 93%

“…The experimental results refer to cylindrical dc neon glow discharges at low pressures. Details of the preparation of the discharge tubes are described in [13]. The discharge current is controlled by means of a current source circuit.…”

Section: Experimental Approachmentioning

confidence: 99%

“…As we will show below, the 1s 2 level plays an important role due to high transition probabilities and an exact knowledge of number densities is required. Additionally, in [13], the resonance radiation output was derived using a radially averaged escape factor [14], i.e., the decay rate of the fundamental radial mode due to radiation. Here, radial variations of the escape factor are considered and we supplement our findings by Monte Carlo simulations employing the algorithm proposed in [15].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Power loss by resonance radiation from a dc neon glow discharge at low pressures and low currents

Franke

Deutsch²,

Dinklage

et al. 2001

Self Cite

Radiative efficiency of emission of resonance radiation from a dc glow discharge plasma is derived experimentally from spatial density profiles of atoms in resonant states. Density profiles are determined by tunable diode laser absorption spectroscopy. Resonance radiation transport is considered both by Lawler and Curry's analytical formula (Lawler J E and Curry J J 1998 J. Phys. D: Appl. Phys. 31 3225) and by Monte Carlo simulations. Radial dependences of the escape factor are studied. Power loss by resonance radiation is found to be about 50% of electrical power input. The impact of resonance radiation on similarity laws in discharge physics is discussed.

“…A third tube has been equipped with quartz windows at the axial ends of the discharge tube, with an anode (which is slit horizontally) and a hollow cathode in a separate part of the tube. Measuring the spectrally resolved optical depth integrated over the length of the column plasma by laser absorption spectroscopy yields absolute densities of the absorbing particles [29,30]. By shifting the tube in the radial direction, the radial variation of the particle densities was obtained.…”

Section: Study Of a Neon Columnmentioning

confidence: 99%

Study of a neon dc column plasma by a hybrid method

Uhrlandt

Franke

2002

The column plasma of a dc glow discharge in neon is comprehensively studied by a new self-consistent hybrid method. The method is based on the solution of the steady-state fluid equations of charge carriers and the Poisson equation using electron transport coefficients and ionization frequencies which arise from a space-dependent kinetic treatment of the electron component. The column description comprises, in addition, a space-dependent treatment of the excited particles in the plasma, the treatment of the plasma-wall interaction processes of the charge carriers and the determination of the electric field. The hybrid method provides a very efficient self-consistent column description although it avoids rough approximations often applied in fluid methods. Results of the method for a neon column plasma are compared with those of probe measurements and spectroscopic studies. The results confirm the importance of the ionization of excited neon atoms for the charge carrier production and emphasize the necessity of the detailed description of the excited states included in the column model.