Betriebsbedingungen für schwingungsfreie Niederdruck‐ Gasentladungen. II. Existenzbereiche der positiven Säule ohne laufende Schichten

Rutscher, A.; Wojaczek, K.

doi:10.1002/ctpp.19640040107

Cited by 25 publications

(2 citation statements)

References 32 publications

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“…For many years they have already been studied in the positive column of low pressure oxygen glow discharges, e.g. [2][3][4][5] or, for example, in SF 6 [6]. Recent measurements focused on the quantitative diagnostics of O − ions, mainly realized by photo-detachment and probe measurements [7,8].…”

Section: Introductionmentioning

confidence: 99%

Investigations on the stability of the low pressure positive column in oxygen

Testrich

Pasedag

Navrátil

et al. 2009

J. Phys. D: Appl. Phys.

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The stability of the low pressure positive column in oxygen was investigated in a pressure range from 0.5 to 0.9 Torr within a discharge current interval from 0.5 to 90 mA. The transition between the well-known T-and H-modes has been studied. The H-to T-mode transition showed a marked hysteresis in the E(I) characteristic which is affected by wall processes. For the first time temporally resolved electric field measurements were realized. At small discharge current the electric field showed a significant modulation, characterized by incoherent fluctuations with a broadband Fourier spectrum. With increasing current the discharge operates in the T-mode, where a mode selection with high modulation degree occurred, resulting in a periodic oscillation of the electric field at a discrete frequency spectrum. The dynamic state in the T-mode is expressed by T-waves moving from the cathode to the anode. It seems that they were excited by oscillations in the cathode region. The waves were damped in the direction of the anode and show no dispersion. The discharge stability was studied using a hydrodynamic model considering electrons, positive and negative ions as well as metastable O 2 (a 1 g) molecules. Here the negative O −-ions play a crucial role. In good agreement with the experiments the transition between the Hand T-modes was explained as a linear unstable equilibrium state where the energy dependence of the corresponding rate coefficients is the driving mechanism (attachment-induced instability).

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Section: Introductionmentioning

confidence: 99%

Investigations on the stability of the low pressure positive column in oxygen

Testrich

Pasedag

Navrátil

et al. 2009

J. Phys. D: Appl. Phys.

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show abstract

“…Nevertheless, these systems are of ongoing interest still today [48][49][50][51][52][53]. It is known that in DC discharges self-excited oscillations may occur over a wide range of frequencies and discharge conditions [54]. Striations are most prominent in molecular gases or in contaminated rare gases, but can also coexist with ionization waves, observed as early as 1841 [55,56].…”

Section: Striations and Ionization Wavesmentioning

confidence: 99%

Ionization waves in the PK-4 direct current neon discharge

Hartmann

Rosenberg

Juhász

et al. 2020

Plasma Sources Sci. Technol.

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The PK-4 system is a micro-gravity dusty plasma experiment currently in operation on-board the International Space Station. The experiment utilizes a long DC discharge in neon or argon gases. We apply our 2D particle-in-cell with Monte Carlo collisions discharge simulation to compute local plasma parameters that serve as input data for future dust dynamics models. The simulation includes electrons, Ne+ ions, and Ne m metastable atoms in neon gas and their collisions at solid surfaces including secondary electron emission and glass wall charging. On the time scale of the on-board optical imaging, the positive column appears stable and homogeneous. On the other hand, our simulations show that on microsecond time scales the positive column is highly inhomogeneous: ionization waves with phase velocities in the range between 500 m s−1 and 1200 m s−1 dominate the structure. In these waves, the electric field and charged particle densities can reach amplitudes up to 10 times of their average value. Our experiments on ground-based PK-4 replica systems fully support the numerical findings. In the experiment, the direction of the DC current can be alternated, which has been found to favor dust particle chain formation. We discuss possible mechanisms for how the highly oscillatory plasma environment contributes to the dust particle chain formation.

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Zum Ähnlichkeitsgesetz der Ionisationswellen

Pfau

Rutscher

1968

Annalen der Physik

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Betriebsbedingungen für schwingungsfreie Niederdruck‐ Gasentladungen. II. Existenzbereiche der positiven Säule ohne laufende Schichten

Cited by 25 publications

References 32 publications

Investigations on the stability of the low pressure positive column in oxygen

Investigations on the stability of the low pressure positive column in oxygen

Ionization waves in the PK-4 direct current neon discharge

Zum Ähnlichkeitsgesetz der Ionisationswellen

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