Electron thermal diffusion instability and standing striations in the plasma of a dc discharge in molecular gases

Urbánkova, H.; Rohlena, K.

doi:10.1007/bf01605622

Cited by 9 publications

(6 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Striations with phase and group velocities directed towards the anode are typically observed in low-pressure dc discharges of molecular gases. An analysis of wave phenomena in a molecular gas discharge can be performed [46,47] using hydrodynamic equations for charged and neutral species and vibrational energy balance for molecules. The linearized system of equations yields a complex dispersion relation for five types of waves.…”

Section: Striation Basicsmentioning

confidence: 99%

“…The dispersion characteristic of the ionization-thermal diffusion wave, ω(k), resembles the usual dispersion of ionization waves in atomic gases for small k but intersects the k-axis (standing striations) for larger k and continues below the axis where it describes the forward anode directed wave. Thus, according to [46], 'the difference between the atomic and molecular gas plasma is essentially a quantitative one. ' Haas [48] presented a comprehensive review of instabilities in molecular and electronegative plasmas.…”

Section: Striation Basicsmentioning

confidence: 99%

See 1 more Smart Citation

Striations in rare gas plasmas

Kolobov¹

2006

J. Phys. D: Appl. Phys.

152

136

View full text Add to dashboard Cite

This paper describes the recent progress in understanding the nature of striations in rare gas plasmas. Striations are ionization waves with unique properties determined by transport phenomena, ionization processes and electron kinetics in current-carrying plasmas. Recent progress in understanding the physics of striations is mainly associated with the advances of non-local electron kinetics in spatially inhomogeneous plasmas and the development of computational models of gas discharges. It has been proven that kinetic analysis of electrons is necessary for nearly all types of striations. Most strikingly, the non-hydrodynamic behaviour of electrons reveals itself in kinetic resonances of the electron distribution function in spatially periodic electric fields, resulting in a variety of striations at low pressures. Moving striations in classical dc discharges have been obtained in computer experiments. Renewed interest in striations has been recently generated by the observation of striations inside pixels of plasma display panels and other micro-plasma devices. High sensitivity of striations to the state of electron gas and ionization kinetics makes them an ideal tool for testing discharge models and advanced plasma diagnostics. Further studies of striations in glow discharges could shed light into the physics of different plasma sources used in modern technologies.There are more things between cathode and anode than are dreamt in your philosophy.H Raether

show abstract

Section: Striation Basicsmentioning

confidence: 99%

Section: Striation Basicsmentioning

confidence: 99%

Striations in rare gas plasmas

Kolobov¹

2006

J. Phys. D: Appl. Phys.

152

136

View full text Add to dashboard Cite

show abstract

“…They predicted stratification driven by Soret and Dufour effects for electron and electron energy transport. In earlier work, Urbankova and Rohlena [20] conducted a similar analysis. They identified that for moderate/low-pressure dc discharge operating in a diatomic gas, the thermal diffusion of electrons plays the most critical role in triggering standing striations.…”

Section: Introductionmentioning

confidence: 93%

“…Following the work of Urbankova and Rohlena [20] we performed a linear stability analysis of the striation behavior in low-pressure dc nitrogen plasmas. From the linear analysis, the dispersion (ω r ) and the application (ω i ) have the following expressions:…”

Section: (B)) the Density Of Nmentioning

confidence: 99%

See 1 more Smart Citation

Striations in moderate pressure dc driven nitrogen glow discharge

Tahiyat¹,

Stephens²,

Kolobov³

et al. 2021

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Plasma stratification has been studied for more than a century. Despite the many experimental studies reported on this topic, theoretical analyses and numerical modeling of this phenomenon have been mostly limited to rare gases. In this work, a one-dimensional fluid model with detailed kinetics of electrons and vibrationally excited molecules is employed to simulate moderate-pressure (i.e. a few Torrs) dc discharge in nitrogen in a 15.5 cm long tube of radius 0.55 cm. The model also considers ambipolar diffusion to account for the radial loss of ions and electrons to the wall. The proposed model predicts self-excited standing striations in nitrogen for a range of discharge currents. The impact of electron transport parameters and reaction rates obtained from a solution of local two-term and a multi-term Boltzmann equation on the predictions are assessed. In-depth kinetic analysis indicates that the striations result from the undulations in electron temperature caused due to the interaction between ionization and vibrational reactions. Furthermore, the vibrationally excited molecules associated with the lower energy levels are found to influence nitrogen plasma stratification and the striation pattern strongly. A balance between ionization processes and electron energy transport allows the formation of the observed standing striations. Simulations were conducted for a range of discharge current densities from ∼0.018 to 0.080 mA cm−2, for an operating pressure of 0.7 Torr. Parametric studies show that the striation length decreases with increasing discharge current. The predictions from the model are compared against experimental measurements and are found to agree favorably.

show abstract