Plasma production from helicon waves

Degeling, A. W.; Jung, C. O.; Boswell, Roderick; Ellingboe, A. R.

doi:10.1063/1.871712

Cited by 152 publications

(164 citation statements)

References 13 publications

(13 reference statements)

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“…The matching circuit was carefully retuned at each setting. These curves show more gentle "jumps" as P rf and B 0 are raised than have been reported by others [5,7]. In the largest jump seen here, between 490 and 540 G in Fig.…”

Section: Nagoya Type III Antennacontrasting

confidence: 35%

“…Over the past decade there has been increasing interest in helicon wave discharges because they have been shown [1][2][3][4][5][6][7] to produce high density plasmas (n > 10 12 cm -3 ) with relatively small amounts of RF power (P rf ≤ 3kW). Theoretical treatments [8,9] of this discharge have been done using the well developed theory of waves in a bounded plasma, giving several scaling laws to which experimental data are fit.…”

Section: Introductionmentioning

confidence: 99%

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2D imaging of a helicon discharge

Blackwell

Chen²

1997

IEEE Conference Record - Abstracts. 1997 IEEE International Conference on Plasma Science

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Two-dimensional images of the ionized argon light of a helicon discharge are made both along and across the magnetic field with various antenna configurations. Two antennas, a Nagoya Type III and a helical antenna, are used to create a magnetized RF plasma with density in the range n ≤ 5 × 10 13 cm -3 . A CCD camera with a 488nm bandpass filter is used to image the plasma as magnetic field and power are changed. By inserting a Faraday shield, it is demonstrated that the inductive component of the antenna coupling is responsible for producing high density plasmas. Asymmetries in the plasma profile are shown to be caused primarily by capacitive coupling, with the purely inductively coupled plasmas being symmetric and centrally peaked. Numerical calculations of antenna coupling show that the configurations having the largest antenna loading correspond to the brightest plasmas observed in the experiment, with the m = +1 mode being the most strongly coupled.

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Section: Nagoya Type III Antennacontrasting

confidence: 35%

Section: Introductionmentioning

confidence: 99%

2D imaging of a helicon discharge

Blackwell

Chen²

1997

IEEE Conference Record - Abstracts. 1997 IEEE International Conference on Plasma Science

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“…High ionization rates also greatly enhance the electrical and mass utilization efficiencies of the propulsion system. Mode transitions, as the RF power applied to the discharge is increased, have been widely reported [12,[14][15][16][17]. As the RF power is increased, discrete 'jumps' in the plasma density are observed when the plasma transitions from the E to the H mode and from the H to the W mode.…”

Section: Operating Modes In Rf Dischargesmentioning

confidence: 96%

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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“…Recent experimental observations 5,[21][22][23] show that the plasma density for helicon plasma sources often peaks several wavelengths downstream from the antenna, and its axial variation can substantially affect the electromagnetic wave field profiles and power absorption of the plasma electrons. It is, therefore, necessary to develop a two-dimensional (r,z) model to account for the effects of the axial variation of the plasma density, temperature, and applied magnetic field on helicon wave propagation and absorption.…”

Section: Introduction To the Two-dimensional "Rz… Simulation Codementioning

confidence: 99%

Wave propagation and absorption simulations for helicon sources

Mouzouris

Scharer

1998

Physics of Plasmas

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A two-dimensional ͑2-D͒, finite-difference computer code is developed to examine helicon antenna coupling, wave propagation, collisionless Landau, and collisional heating mechanisms. The code calculates the electromagnetic wave fields and power absorption in an inhomogeneous, cold, collisional plasma. The current distribution of the launching antenna, which provides the full antenna spectra, is included in the model. An iterative solution that incorporates warm plasma thermal effects has been added to the code to examine the contribution of collisionless ͑Landau͒ wave absorption by electrons. Detailed studies of the wave fields and electron heating profiles at low magnetic fields (B 0 Ͻ100 G), where both Trivelpiece-Gould ͑TG͒ and helicon ͑H͒ modes are present, are discussed. The effects of the applied uniform magnetic field (B 0 ϭ10-1000 G), 2-D (r,z) density profiles (n e0 ϭ10 11 -10 13 cm Ϫ3 ), neutral gas pressures of 1-10 mTorr and the antenna spectrum on collisional and collisionless wave field solutions and power absorption are investigated. Cases in which the primarily electrostatic ͑TG͒ surface wave dominates the heating and the power is absorbed near the edge region and cases in which the propagating helicon wave transports and deposits its energy in the core plasma region are examined.

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Plasma production from helicon waves

Cited by 152 publications

References 13 publications

2D imaging of a helicon discharge

2D imaging of a helicon discharge

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

Wave propagation and absorption simulations for helicon sources

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