Time-resolved ion velocity distribution in a cylindrical Hall thruster: Heterodyne-based experiment and modeling

Diallo, A.; Keller, S.; Shi, Yuan; Raitses, Yevgeny; Mazouffre, S.

doi:10.1063/1.4914829

Cited by 32 publications

(22 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A sinusoidal modulation of 3-30 V is externally applied on top of the 220 V anode potential at a given frequency ω D . The technique then assumes a decomposition of the ion IVDF f (t, x, v) into harmonics of ω D [27]:…”

Section: 32mentioning

confidence: 99%

Time-resolved laser-induced fluorescence diagnostics for electric propulsion and their application to breathing mode dynamics

Young¹,

Fabris²,

MacDonald-Tenenbaum³

et al. 2018

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

Several techniques have been developed recently for performing time-resolved laser-induced fluorescence (LIF) measurements in oscillating plasmas. One of the primary applications is characterizing plasma fluctuations in devices like Hall thrusters used for space propulsion. Optical measurements such as LIF are nonintrusive and can resolve properties like ion velocity distribution functions with high resolution in velocity and physical space. The goals of this paper are twofold. First, the various methods proposed by the community for introducing time resolution into the standard LIF measurement of electric propulsion devices are reviewed and compared in detail. Second, one of the methods, the sample-hold technique, is enhanced by parallelizing the measurement hardware into several signal processing channels that vastly increases the data acquisition rate. The new system is applied to study the dynamics of ionization and ion acceleration in a commercial BHT-600 Hall thruster undergoing unforced breathing mode oscillations in the 44-49 kHz range. A very detailed experimental picture of the common breathing mode ionization instability emerges, in close agreement with established theory and numerical simulations.

show abstract

Section: 32mentioning

confidence: 99%

Time-resolved laser-induced fluorescence diagnostics for electric propulsion and their application to breathing mode dynamics

Young¹,

Fabris²,

MacDonald-Tenenbaum³

et al. 2018

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…The ion velocity distribution function (IVDF) using LIF. 13 A tunable diode laser is used to pump the 5d 2 F 7/2 Xe + metastable level to 6p 2 D 0 5/2 . The laser beam was aligned perpendicular to the thruster exit plane and was injected into the thruster channel at along the thruster axis.…”

Section: B Time-resolving Laser-induced Uorescencementioning

confidence: 99%

Measurements and theory of driven breathing oscillations in a Hall effect thruster

Hara¹,

Keller²,

Raitses³

2016

52nd AIAA/SAE/ASEE Joint Propulsion Conference

View full text Add to dashboard Cite

Breathing mode oscillations in Hall eect thrusters occur depending on the operation parameters such as discharge voltage, anode mass ow, and magnetic eld. Time-dependent laser-induced uorescence is used to measure the ion velocity distribution functions (IVDFs) with a modulating anode voltage. [Diallo et al. RSI 2015] Experimental results suggest that the IVDFs vanish or shifts its peak to a small velocity near the maximum peak of the discharge current oscillation. A zero-dimensional plasma global model [Hara et al. PoP 2014] is used to analyze the ionization oscillation mode by forcing the electric eld to oscillate with a certain strength and frequency. In this model, the neutral atom continuity equation, the ion continuity and momentum equations, and electron energy equation are taken into account. Global model suggests that the ion mean velocity can uctuate in time and is in-phase with the electric eld oscillation. A 1D hybrid simulation shows that there can be a region where ion distribution exists in slow velocity (∼1000 m/s) due to reversed electric eld during the oscillation.

show abstract

“…The correlation between the amplitude of current oscillations and the thruster performance is not so clear, but it is known that high performance regimes are not free of breathing oscillations. 9,10 Breathing can be synchronized via application of the external modulations of the anode [11][12][13] or the cathode-keeper voltage. 14 This technique has been used in Time-Resolved Laser-Induced Fluorescence (TR-LIF) diagnostics for the studies of breathing 15,16 oscillations.…”

Section: Introductionmentioning

confidence: 99%

On limitations of laser-induced fluorescence diagnostics for xenon ion velocity distribution function measurements in Hall thrusters

et al. 2018

Self Cite

View full text Add to dashboard Cite

Hall thruster operation is characterized by strong breathing oscillations of the discharge current, the plasma density, the temperature, and the electric field. Probe- and laser-induced fluorescence (LIF) diagnostics were used to measure temporal variations of plasma parameters and the xenon ion velocity distribution function (IVDF) in the near-field plasma plume in regimes with moderate (<18%) external modulations of applied DC discharge voltage at the frequency of the breathing mode. It was shown that the LIF signal collapses while the ion density at the same location is finite. The proposed explanation for this surprising result is based on a strong dependence of the excitation cross-section of metastables on the electron temperature. For large amplitudes of oscillations, the electron temperature at the minimum enters the region of very low cross-section (for the excitation of the xenon ions); thus, significantly reducing the production of metastable ions. Because the residence time of ions in the channel is generally shorter than the time scale of breathing oscillations, the density of the excited ions outside the thruster is low and they cannot be detected. In the range of temperature of oscillations, the ionization cross-section of xenon atoms remains sufficiently large to sustain the discharge. This finding suggests that the commonly used LIF diagnostic of xenon IVDF can be subject to large uncertainties in the regimes with significant oscillations of the electron temperature, or other plasma parameters.

show abstract

Time-resolved ion velocity distribution in a cylindrical Hall thruster: Heterodyne-based experiment and modeling

Cited by 32 publications

References 11 publications

Time-resolved laser-induced fluorescence diagnostics for electric propulsion and their application to breathing mode dynamics

Time-resolved laser-induced fluorescence diagnostics for electric propulsion and their application to breathing mode dynamics

Measurements and theory of driven breathing oscillations in a Hall effect thruster

On limitations of laser-induced fluorescence diagnostics for xenon ion velocity distribution function measurements in Hall thrusters

Contact Info

Product

Resources

About