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Sinkevich, O. A.; Sosnin, V. E.

doi:10.1023/a:1017506329000

Cited by 6 publications

(3 citation statements)

References 2 publications

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“…Discrete plasma structures have been reported at lower microwave frequencies in the past [14][15][16][17] with some attempts to theoretically explain the emergence of such structures. [18][19][20][21] Some of these results are similar to the 110 GHz breakdown plasmas reported here in terms of the direction of filamentation. Yet, the clarity and regularity of the plasma filamentary array generated by the 110 GHz microwaves reported here are unprecedented and are not adequately explained by these theories.…”

Section: Discussionsupporting

confidence: 78%

Plasma structures observed in gas breakdown using a 1.5 MW, 110 GHz pulsed gyrotron

et al. 2009

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Regular two-dimensional plasma filamentary arrays have been observed in gas breakdown experiments using a pulsed 1.5 MW, 110 GHz gyrotron. The gyrotron Gaussian output beam is focused to an intensity of up to 4 MW/cm2. The plasma filaments develop in an array with a spacing of about one quarter wavelength, elongated in the electric field direction. The array was imaged using photodiodes, a slow camera, which captures the entire breakdown event, and a fast camera with a 6 ns window. These diagnostics demonstrate the sequential development of the array propagating back toward the source. Gases studied included air, nitrogen, SF6, and helium at various pressures. A discrete plasma array structure is observed at high pressure, while a diffuse plasma is observed at lower pressure. The propagation speed of the ionization front for air and nitrogen at atmospheric pressure for 3 MW/cm2 was found to be of the order of 10 km/s.

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Section: Discussionsupporting

confidence: 78%

Plasma structures observed in gas breakdown using a 1.5 MW, 110 GHz pulsed gyrotron

et al. 2009

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“…Studies of the stability of gas discharges in low-temperature plasma physics are less common and refer usually to the bulk of the discharge (see, e.g. books [1,2] and references therein; one can mention [3][4][5][6][7] as examples of more recent works).…”

Section: Introductionmentioning

confidence: 99%

Stability of direct current transfer to thermionic cathodes: I. Analytical theory

Benilov¹

2007

J. Phys. D: Appl. Phys.

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Stability of different modes of steady-state current transfer to cathodes of high-pressure arc discharges is investigated in the framework of the model of nonlinear surface heating. An eigenvalue problem governing perturbations has been formulated and its properties analysed. It is shown that the spectrum of this problem is real, therefore the change of stability can occur only at bifurcation points, in which different modes of steady-state current transfer join each other. Analytical expressions describing behaviour of the increment in the vicinity of bifurcation points have been derived. A general pattern of stability of the diffuse mode of current transfer to axially symmetric cathodes and of 3D spot modes branching off from the diffuse mode is established. Theoretical predictions are found to be in agreement with trends observed in the experiment and it is shown that the recently published comparison of the theory and the experiment on the spot mode needs to be revisited.

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“…Also, the present study differs substantially from these studies in terms of time scales (3 s vs 0.05-20 ms) as well as intensities (on the order of 10 6 vs 10 4 W=cm 2 ) used for initiating and sustaining the breakdown plasma. A number of theoretical studies have also been reported to explain the structures such as ''snakes'' and ''chains'' that have been observed in high-pressure microwave breakdown research [11][12][13]. These explanations emphasize the role of plasma kinetics and instabilities.…”

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confidence: 99%

Observation of Large Arrays of Plasma Filaments in Air Breakdown by 1.5-MW 110-GHz Gyrotron Pulses

et al. 2008

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We report the observation of two-dimensional plasma filamentary arrays with more than 100 elements generated during breakdown of air at atmospheric pressure by a focused Gaussian beam from a 1.5-MW, 110-GHz gyrotron operating in 3-s pulses. Each element is a plasma filament elongated in the electric field direction and regularly spaced about one-quarter wavelength apart in the plane perpendicular to the electric field. The development of the array is explained as a result of diffraction of the beam around the filaments, leading to the sequential generation of high intensity spots, at which new filaments are created, about a quarter wavelength upstream from each existing filament. Electromagnetic wave simulations corroborate this explanation and show very good correlation to the observed pattern of filaments.

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Cited by 6 publications

References 2 publications

Plasma structures observed in gas breakdown using a 1.5 MW, 110 GHz pulsed gyrotron

Plasma structures observed in gas breakdown using a 1.5 MW, 110 GHz pulsed gyrotron

Stability of direct current transfer to thermionic cathodes: I. Analytical theory

Observation of Large Arrays of Plasma Filaments in Air Breakdown by 1.5-MW 110-GHz Gyrotron Pulses

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