Microdischarges with plane cathodes

Biborosch, L.; Bilwatsch, O.; Ish-Shalom, Shlomo; Dewald, E. L.; Ernst, U.; Frank, K.

doi:10.1063/1.125496

Cited by 23 publications

(15 citation statements)

References 5 publications

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“…Peak electron densities of up to 5ϫ10 16 cm Ϫ3 have been measured for pulsed atmospheric argon discharges, far exceeding those in other nonequilibrium high-pressure glow discharges. The sustaining voltage is only on the order of several hundred volts, and the current ranges from microamperes in the predischarge mode to amperes in the pulsed, abnormal glow mode.…”

Section: Discussionmentioning

confidence: 90%

Microhollow cathode discharges

Schoenbach¹,

Moselhy²,

Shi³

et al. 2003

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Section: Discussionmentioning

confidence: 90%

Microhollow cathode discharges

Schoenbach¹,

Moselhy²,

Shi³

et al. 2003

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…Microdischarge ͑MD͒ devices take advantage of the pd (pressureϫelectrode separation͒ scaling of low temperature partially ionized plasmas to operate stably as glow discharges at pressures approaching and exceeding atmospheric with dimensions as small as 10s m. [1][2][3][4][5][6][7][8][9] MDs having characteristic dimensions of tens to hundreds of m have been developed which operate at 100s Torr to as much as 1000 Torr in rare gas, rare gas-halogen, and molecular gas mixtures on a continuous basis. Early variants of MDs were constructed with the intent to operate as miniature hollow cathodes by reducing the cathode diameter while increasing the pressure to maintain the same pd as conventional low pressure hollow cathode devices.…”

Section: Introductionmentioning

confidence: 99%

Modeling of microdischarge devices: Pyramidal structures

Kushner

2004

Journal of Applied Physics

149

143

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Microdischarge ͑MD͒ devices are plasma sources typically operating at 100s Torr to atmospheric pressure with dimensions of 10s-100s m. Their design in based on pd (pressureϫcharacteristic dimension͒ scaling; smaller dimensions are enabled by higher operating pressures with typical devices operating with pdϭ1 -10 Torr cm. MD devices have exhibited behavior that resemble both Townsend and hollow-cathode discharges, with bulk and beam electrons providing the dominant excitation, respectively. In this article, results from a two-dimensional computational study of MD devices operating in neon using a pyramidal cathode structure are discussed. Pressures of 400-1000 Torr and device dimensions of 15-40 m are investigated. The onset of behavior resembling negative glow discharges with decreasing pressure correlates with an extension of cathode fall accelerated beam electrons into the bulk plasma. For constant applied voltage, peak electron densities increase with increasing pressure as the beam electrons are slowed in more confined regions. The MD devices typically require higher applied voltages to operate at lower pressures, and so resemble discharges obeying Paschen's curve for breakdown. MD devices having similar magnitudes and spatial distributions of plasma and excited state densities can be obtained to dimensions of Ͻ15 m by keeping pd and current density constant, and having a cathode fall thickness small compared to the characteristic dimension.

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“…An important class of plasma discharges, called microdischarges, has gained considerable interest in the plasma community over the past decade [1][2][3][4][5][6][7][8][9][10][11]. Microdischarges produce stable, self-sustaining, highly non-equilibrium plasmas at length scales of ∼10's-100's µm, pressures of ∼10's-100's Torr, current densities upto ∼10 5 A/m 2 and power densities ∼10 12 W/m 3 [12,13].…”

Section: Introductionmentioning

confidence: 99%

Simulation of Direct‐Current Microdischarges for Application in Electro‐Thermal Class of Small Satellite Propulsion Devices

Kothnur

Raja

2007

Contrib. Plasma Phys.

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Microdischarges are miniature non-equilibrium plasma discharges with characteristic dimensions of ∼10's-100's µm and relatively high operating pressures of ∼10's-100's Torr. Microdischarges possess several unique properties that have been exploited in a number of new applications. We have recently proposed a microdischargebased electro-thermal class of microthrusters for small satellite propulsion. These devices utilize intense gas heating in microdischarges to preheat a propellant gas stream before it is expanded in a micronozzle to produce thrust; thereby improving specific impulse of the device over a conventional cold gas microthruster. This paper addresses direct-current microdischarge phenomena in a flowing gas stream. A two-dimensional, selfconsistent, fluid model of a helium microdischarge in a bulk gas flow is developed. For relatively high current/power levels considered in this study, the microdischarge operates in an abnormal glow mode with positive differential resistivity. Increasing discharge pressures for fixed power and bulk flow rates results in a decrease in charged species densities and the electron and gas temperatures. Also the discharge becomes increasingly constricted with increasing pressures, resulting in a more normal glow mode-like operation. Increasing bulk flow rates results in exactly the same trends as increasing pressures. For given input power and pressure, there exists an optimum flow rate for which the average outlet gas temperature from the discharge is a maximum. An increase in input electrical power results in an almost linear increase in the gas temperatures; this property of microdischarges is the key feature that is exploited in our microdischarge-based thruster concept.

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Microdischarges with plane cathodes

Cited by 23 publications

References 5 publications

Microhollow cathode discharges

Microhollow cathode discharges

Modeling of microdischarge devices: Pyramidal structures

Simulation of Direct‐Current Microdischarges for Application in Electro‐Thermal Class of Small Satellite Propulsion Devices

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