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Microwave Cavities Generated Active Species in Plasmas

2025· book-chapter· en· W4408912455 on OpenAlexaboutno aff
André Ricard

Bibliographic record

Venuenot available
Typebook-chapter
Languageen
FieldEngineering
TopicParticle accelerators and beam dynamics
Canadian institutionsnot available
Fundersnot available
KeywordsPlasmaMicrowaveEnvironmental scienceMaterials sciencePhysicsNuclear physicsQuantum mechanics

Abstract

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Microwave plasma sources are described from low Ar gas pressure (< 1 Torr) to high gas pressures (> 10 Torr up to the atmospheric gas pressure) in N2 and Ar. At low gas pressure, the plasma diameter is over 1 cm, typically 2.6 cm and at high gas pressure, it needs discharge tubes < 1cm, down to 0.1 cm. The microwave plasmas have been studied from low to atmospheric gas pressure in rare gases (mainly Ar) and gas mixtures containing N2. At low gas pressure, it is found the surface wave plasmas, produced by patented launchers Surfatron and Surfaguide, which were developed by Michel Moisan in the Plasmas Lab. of the Montreal Univ. in 1975 [1] . At high gas pressure from a few Torr up to the atmospheric gas pressure, the SW plasmas Surfatron at low power and Surfaguide at high power are still operating. It is also given the results obtained by a resonant cavity in N2 - xO2 with x = 0-20%. It is presently reported the detection of plasma active species obtained by optical spectroscopy. The main used frequency was 2450 MHz. The plasma power could vary from a few Watts (surfatron) up to a few 103 Watts (Surfaguide, resonant cavity). The plasma can be produced in a static gas flow, mainly at low gas pressure and up to several liters per minute (slpm) at high gas pressures. The optical spectroscopy was set up first to obtain the spatial distribution of radiative species, mainly in Ar gas at low gas pressure in the perspective to characterize the SW plasmas. Then the radial distribution of Ar metastable density was obtained by resonant optical absorption. At medium (a few Torr) up to the atmospheric gas pressure, flowing HF plasmas (resonant cavity) and SW plasmas were produced in gas mixtures with N2 to produce N -atoms and other active species such as N2 metastable molecules and N2+ions which are studied inside the plasma and in afterglow conditions. It discusses the kinetics reactions relating the N2(X,v),N2(A,v'),N2(B,v'),N2(C,v'),N2+(X,v') and N2+(B,v') interfering in the radiative emissions of N2(B,v'),N2(C,v') and N2+(B,v') states. At atmospheric gas pressure, the plasmas are mainly in Ar dominant gas, easier to ionize. In these conditions, the plasmas are characterized by the electron density and the gas temperature which will be reported for specific microwave plasmas sources. Depending on plasma parameters such as powers, flow rates and exit tube diameters, the plasmas were more and less near the Local Thermodynamic Equilibrium (LTE) as demonstrated in Montreal Univ., Lisbon IST and Cordoba Univ. The conclusion was that the N2 excited states are mainly produced from the N2 ground state by electron collisions in a resonant microwave cavity. It was estimated that the LTE was nearly reached in a 100 Torr, 300-500 W N2 plasma in a quartz tube of i.d.10 mm. with equality of vibrational and rotational temperatures.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.003
Threshold uncertainty score0.011

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.001
Scholarly communication0.0000.001
Open science0.0010.001
Research integrity0.0010.000
Insufficient payload (model declined to judge)0.0030.001

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.015
GPT teacher head0.196
Teacher spread0.181 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

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Citations0
Published2025
Admission routes1
Has abstractyes

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