How to determine the relative ion concentrations of multiple-ion-species plasmas generated in the multi-dipole filament source

Kim, Nam Kyun; Huh, Sung-Ryul; Roh, Hyun-Joon; Park, Seolhye; Kim, Gon−Ho

doi:10.1088/0022-3727/48/22/225201

Cited by 9 publications

(10 citation statements)

References 23 publications

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“…Neutral damping of the two-stream instability was identified as the mechanism that causes the ion flow speeds to separate with increasing pressure, eventually reaching their individual sound speeds at high neutral pressure. The PIC-MCC simulations suggest this theory is accurate when charge exchange collisions are included, and therefore could be used in the interpretation of experimental diagnostics, the design of plasma-based materials processing tools, and in global plasma models, 35 all of which depend on the accurate modeling of ion flow speeds at the sheath edge. These results may also contribute to progress in modeling plasma-boundary interactions in plasmas with more than two ion species.…”

Section: Discussionmentioning

confidence: 99%

Influence of neutral pressure on instability enhanced friction and ion velocities at the sheath edge of two-ion-species plasmas

Adrian

Lafleur

2017

Physics of Plasmas

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The Instability Enhanced Friction theory [Baalrud et al., Phys. Rev. Lett. 103, 205002 (2009)] is extended to account for the influence of neutral pressure in predicting the flow speed of each ion species at the sheath edge of plasmas containing two ion species. Particle-in-cell simulations show that the theory accurately predicts both the neutral pressure cutoff of ion-ion two-stream instabilities and the ion flow speeds at the sheath edge as pressure is varied over several orders of magnitude. The simulations are used to directly calculate the instability-enhanced ion-ion friction force. At sufficiently high neutral pressure, the simulations also provide evidence for collisional modifications to the Bohm criterion.

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Section: Discussionmentioning

confidence: 99%

Influence of neutral pressure on instability enhanced friction and ion velocities at the sheath edge of two-ion-species plasmas

Adrian

Lafleur

2017

Physics of Plasmas

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“…One should note that with a filament discharge, the EEDFs contain Maxwellian electrons and primary electrons. The primary electrons are the main source of ionization [27,28] and the tail of the Maxwellian provides little contribution to plasma production. Therefore, Maxwellian EEDFs are maintained even at very low degrees of ionization.…”

Section: Methodsmentioning

confidence: 99%

Experimental investigation of sheath effects on I–V traces of strongly electron emitting probes

Yip

Jin

Zhang

et al. 2020

Plasma Sources Sci. Technol.

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I-V traces of strongly emitting emissive probes are investigated in a multidiople filament discharge. It is found that at sufficiently high neutral pressure and emitting current, the variation of the I-V traces and their associated inflection points no longer follow the previous predictions of space charge limited (SCL) models. A new, steep slope region of the I-V trace appears near the plasma potential when the probe is strongly emitting, causing the inflection point and the floating potential to increase towards the plasma potential as emission current increases, rather than staying constant. This is, to our knowledge, the first experimental evidence that the effects predicted by Campanell et al's inverse sheath theory (2017 Physics of Plasmas 24 057101) not only affect the floating potential but also a region in the I-V trace of an emissive probe. It is also found that the double inflection point structure when the probe is biased below the ionization energy of the working gas is highly likely to be an emission retardation effect from enhanced virtual cathode formation due to the increased local electron density. The implications of these findings on hot cathode sources are briefly discussed.

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“…In addition to this evidence provided by the ion speed measurements, the presence of two-stream instabilities have been directly measured using Langmuir probes [75,94]. The observed modification of ion speeds at the sheath edge has important implications for plasma boundary interactions, as well as global plasma models [144].…”

Section: Plasma With Multiple Ion Speciesmentioning

confidence: 99%

Interaction of biased electrodes and plasmas: sheaths, double layers, and fireballs

Baalrud

Scheiner

Yee

et al. 2020

Plasma Sources Sci. Technol.

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Biased electrodes are common components of plasma sources and diagnostics. The plasma-electrode interaction is mediated by an intervening sheath structure that influences properties of the electrons and ions contacting the electrode surface, as well as how the electrode influences properties of the bulk plasma. A rich variety of sheath structures have been observed, including ion sheaths, electron sheaths, double sheaths, double layers, anode glow, and fireballs. These represent complex self-organized responses of the plasma that depend not only on the local influence of the electrode, but also on the global properties of the plasma and the other boundaries that it is in contact with. This review summarizes recent advances in understanding the conditions under which each type of sheath forms, what the basic stability criteria and steady-state properties of each are, and the ways in which each can influence plasma-boundary interactions and bulk plasma properties. These results may be of interest to a number of application areas where biased electrodes are used, including diagnostics, plasma modification of materials, plasma sources, electric propulsion, and the interaction of plasmas with objects in space.

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How to determine the relative ion concentrations of multiple-ion-species plasmas generated in the multi-dipole filament source

Cited by 9 publications

References 23 publications

Influence of neutral pressure on instability enhanced friction and ion velocities at the sheath edge of two-ion-species plasmas

Influence of neutral pressure on instability enhanced friction and ion velocities at the sheath edge of two-ion-species plasmas

Experimental investigation of sheath effects on I–V traces of strongly electron emitting probes

Interaction of biased electrodes and plasmas: sheaths, double layers, and fireballs

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