Operating the Helicon Double Layer Thruster in a Space Simulation Chamber

Charles, Christine; Boswell, Roderick; Alexander, Peter; Costa, Carlos H.; Sutherland, Orson; Pfitzner, Leigh; Franzen, René; Kingwell, Jeff; Parfitt, A.J.; Frigot, Pierre-Etienne; Amo, J. Del; Saccoccia, G.

doi:10.1109/tps.2008.924425

Cited by 20 publications

(12 citation statements)

References 9 publications

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“…The transition here occurs at similar RF power to that observed during the tests of the HDLT prototype at ESTEC [11]. The density measured in the source is an order of magnitude lower than that which was estimated in the source during the ESTEC tests, however the operating pressure was significantly lower in that instance (0.015 mTorr to 0.15 mTorr compared with 0.45 mTorr here).…”

Section: Source Characterizationsupporting

confidence: 63%

High density mode in xenon produced by a Helicon Double Layer Thruster

West¹,

Charles²,

Boswell³

2009

J. Phys. D: Appl. Phys.

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A high density 'blue' mode has been observed when operating the Helicon Double Layer Thruster (HDLT) with xenon. Using a Langmuir probe and a retarding field energy analyser (RFEA), the plasma source and exhaust have been characterized at various radio frequency (RF) powers and operating pressures. When operating at low RF powers, the HDLT prototype is shown to be in a capacitively coupled mode. As the RF power is increased, a discrete mode transition occurs over a small RF power range (at about 625 W at 0.45 mTorr) and the plasma inside the source increases in density significantly and changes to a bright white/blue colour. This high density mode exhibits hysteresis, and radial measurements inside the source reveal a centrally peaked profile that is indicative of a helicon wave-sustained discharge. The quality, or Q, factor of the matching box is determined as a function of RF power and is shown to decrease in the high density mode, consistent with the increase in plasma density observed. The xenon exhaust of the HDLT prototype is investigated axially with the Langmuir probe and the RFEA and is shown to follow a Boltzmann expansion with an electron temperature of about 6 eV.

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Section: Source Characterizationsupporting

confidence: 63%

High density mode in xenon produced by a Helicon Double Layer Thruster

West¹,

Charles²,

Boswell³

2009

J. Phys. D: Appl. Phys.

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“…24 The thrust generated by the ion beam has been a subject of detailed study because of its potential for commercial application. 25 In previous studies using RFEAs, detachment of the ion beam from the expanding magnetic field lines has been observed, 26 with beam divergences of less than 6 degrees. 27 In this work, we present high resolution, twodimensional mapping of IVDFs and the electric field in the plume of an expanding helicon source plasma at low neutral pressure.…”

Section: Introductionmentioning

confidence: 94%

Spatial structure of ion beams in an expanding plasma

et al. 2017

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We report spatially resolved perpendicular and parallel, to the magnetic field, ion velocity distribution function (IVDF) measurements in an expanding argon helicon plasma. The parallel IVDFs, obtained through laser induced fluorescence (LIF), show an ion beam with v ≈ 8000 m/s flowing downstream and confined to the center of the discharge. The ion beam is measurable for tens of centimeters along the expansion axis before the LIF signal fades, likely a result of metastable quenching of the beam ions. The parallel ion beam velocity slows in agreement with expectations for the measured parallel electric field. The perpendicular IVDFs show an ion population with a radially outward flow that increases with distance from the plasma axis. Structures aligned to the expanding magnetic field appear in the DC electric field, the electron temperature, and the plasma density in the plasma plume. These measurements demonstrate that at least two-dimensional and perhaps fully three-dimensional models are needed to accurately describe the spontaneous acceleration of ion beams in expanding plasmas.

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“…9 A new type of plasma thruster, the helicon double layer thruster ͑HDLT͒, has been recently developed and tested for a variety of gases. [10][11][12] Electric propulsion of spacecraft is employed when a small thrust with a high specific impulse is appropriate to the mission profile: e.g., station keeping and long range interplanetary trajectories. One source of fuel and energy inefficiency in rocket propulsion is divergence of the exhaust plume.…”

mentioning

confidence: 99%

Spatial retarding field energy analyzer measurements downstream of a helicon double layer plasma

Cox¹,

Charles²,

Boswell³

et al. 2008

Applied Physics Letters

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Spatial ion energy measurements using a retarding field energy analyzer are performed in the exhaust of a 0.30mTorr, 250W helicon double layer plasma to investigate the divergence of the argon ion beam formed by acceleration in the double layer. Various divergence angles are computed by considering the radial distribution of beam density; the average beam ion diverging by 9°. The efficiency at which momentum is imparted parallel to the longitudinal axis of the thruster is calculated to be 98%. The results show that a few centimeters downstream of the source, the beam ions do not follow the magnetic field lines.

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Operating the Helicon Double Layer Thruster in a Space Simulation Chamber

Cited by 20 publications

References 9 publications

High density mode in xenon produced by a Helicon Double Layer Thruster

High density mode in xenon produced by a Helicon Double Layer Thruster

Spatial structure of ion beams in an expanding plasma

Spatial retarding field energy analyzer measurements downstream of a helicon double layer plasma

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