Background Pressure Effects on Ion Velocity Distribution Within a Medium-Power Hall Thruster

Nakles, Michael R.; Hargus, William A.

doi:10.2514/1.48027

Cited by 59 publications

(78 citation statements)

References 14 publications

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“…Both modes are believed to be tied to ionization processes in the Hall thruster because their frequencies are in the kilohertz to tens of kilohertz range, which is most closely related to the characteristic ion and neutral transit time across the discharge axial length scale. 6,12 Recently, there is a new surge of interest in these plasma oscillations because they have been observed to vary greatly with facility conditions 18 and may drive differences between thruster behavior in ground tests and on orbit. As more Hall thrusters are being considered for flight applications, including the HiVHAc series, it has become critical for the Hall thruster community to better understand the behavior of these plasma oscillations so that on-orbit performance can be predicted using ground test data.…”

Section: Past Workmentioning

confidence: 99%

“…For a typical Hall thruster, the acceleration/ionization zone length is a few tens of millimeters. 18,27,28 Assuming a few millimeters change in the acceleration/ionization zone length correspond to a few millimeters change in the erosion band length and assuming the design margin on the erosion band length was chosen to be a few millimeters, one can establish 0.9 as the limit for how much change in normalized length scale is considered acceptable. Using Fig.…”

Section: A Correlating Breathing Mode Frequency To Wear Mechanics Anmentioning

confidence: 99%

“…6 Since the 1960's, many studies have been performed to characterize these oscillations. [7][8][9][10][11][12][13][14][15][16][17][18][19][20] Yet the roles of these oscillations in relation to thruster performance and life time are still largely unknown. Currently, there are two oscillation modes that are believed to be important to Hall thruster operations, the "breathing" mode and the "spokes" mode.…”

Section: Past Workmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Background Pressure on the Plasma Oscillation Characteristics of the HiVHAc Hall Thruster

Huang¹,

Kamhawi²,

Lobbia³

et al. 2014

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)Air Force Research Laboratory (AFMC) AFRL/RQR 5 Pollux Drive SPONSOR/MONITOR'S REPORTEdwards AFB CA 93524-7048 NUMBER(S) AFRL-RQ-ED-TP-2014-226 DISTRIBUTION / AVAILABILITY STATEMENTDistribution A: Approved for Public Release; Distribution Unlimited SUPPLEMENTARY NOTESTechnical paper presented at 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Cleveland, OH, 28-30 July, 2014. PA#14392 ABSTRACTDuring a single-string integration test of the NASA HiVHAc Hall thruster, a number of plasma diagnostics were implemented to study the effect of varying facility background pressure on thruster operation. These diagnostics characterized the thruster performance, the plume, and the plasma oscillations in the thruster. Thruster performance and plume characteristics as functions of background pressure were previously published. This paper will focus on changes in the plasma oscillation characteristics with changing background pressure. The diagnostics used to study plasma oscillations include a high-speed camera and a set of high-speed Langmuir probes. The results show a rise in the oscillation frequency of the "breathing" mode with rising background pressure, which is hypothesized to be due to a shortening acceleration/ionization zone. An attempt is made to apply a simplified ingestion model to the data. The combined results are used to estimate the maximum acceptable background pressure for performance and wear testing. During a single-string integration test of the NASA HiVHAc Hall thruster, a number of plasma diagnostics were implemented to study the effect of varying facility background pressure on thruster operation. These diagnostics characterized the thruster performance, the plume, and the plasma oscillations in the thruster. Thruster performance and plume characteristics as functions of background pressure were previously published. This paper will focus on changes in the plasma oscillation characteristics with changing background pressure. The diagnostics used to study plasma oscillations include a high-speed camera and a set of high-speed Langmuir probes. The results show a rise in the oscillation frequency of the "breathing" mode with rising background pressure, which is hypothesized to be due to a shortening acceleration/ionization zone. An attempt is made to apply a simplified ingestion model to the data. The combined results are used to estimate the maximum acceptable background pressure for performance and...

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Section: Past Workmentioning

confidence: 99%

Section: A Correlating Breathing Mode Frequency To Wear Mechanics Anmentioning

confidence: 99%

Section: Past Workmentioning

confidence: 99%

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Effect of Background Pressure on the Plasma Oscillation Characteristics of the HiVHAc Hall Thruster

Huang¹,

Kamhawi²,

Lobbia³

et al. 2014

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“…The gradients around the exit are fairly large, and the two nozzle exit lips are singularity points where the density drops rapidly to the background density outside the nozzle. Figures 8-11 present several jet centerline properties, calculated with Equations (7), (8), (10) and (11). The parameters are: n b /n 0 = 0.2, S 0 = 2, S b = 1, T 0 = 200 Kelvin, and T b = 300 Kelvin, and the background flow direction α 0 varies to demonstrate the background flow effects on the primary jet flows.…”

Section: Validations and Discussion On The Derived Formulasmentioning

confidence: 99%

“…The work includes two parts: (1) quantify the background flow or facility effects on a weak jet; and (2) more importantly, recover the related parameters from limited measurements, and with these recovered parameters, the whole flowfield can be recovered, by applying Equations (7)- (11).…”

Section: Discussionmentioning

confidence: 99%

A New Gaskinetic Model to Analyze Background Flow Effects on Weak Gaseous Jet Flows from Electric Propulsion Devices

Cai

2017

Aerospace

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Recent work on studying rarefied background and jet flow interactions is reported. A new gaskinetic method is developed to investigate two closely related problems. The first problem is how a collisionless background flow can affect a highly rarefied jet flow. The rarefied jet and background flow conditions are assumed available and described with seven parameters. Gaskinetic theories are applied and formulas are obtained for the mixture properties. Simulations are performed to validate these expressions, and excellent agreement is obtained. The second problem is to recover the collisionless background and jet flow parameters with limited measurements. A group of linearized equations are derived for the flowfield properties. The solving process includes initial estimations on the seven parameters, followed with iterations. Numerical tests are performed and the results indicate the procedure is accurate and efficient. The new method and expressions can reduce the amount of experimental work and numerical simulations to analyze facility effects. Parameter studies with particle simulations may require several months; however, the new methods may require minutes. These methods can be used to quantify and predict jet performance, vacuum chamber designs and optimization. Applications may be for many societies using vacuum conditions.

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Non-intrusive tools for electric propulsion diagnostics

et al. 2021

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Background Pressure Effects on Ion Velocity Distribution Within a Medium-Power Hall Thruster

Cited by 59 publications

References 14 publications

Effect of Background Pressure on the Plasma Oscillation Characteristics of the HiVHAc Hall Thruster

Effect of Background Pressure on the Plasma Oscillation Characteristics of the HiVHAc Hall Thruster

A New Gaskinetic Model to Analyze Background Flow Effects on Weak Gaseous Jet Flows from Electric Propulsion Devices

Non-intrusive tools for electric propulsion diagnostics

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