Radial Distributions of Active Species in RF-Jet Plasmas and Afterglows
Bibliographic record
Abstract
The radial distributions of plasma and afterglow radiative species have been analyzed with optical fibers connected to an optical spectrometer. With an optical fiber of 1 mm dia. giving a detected light resolution of about 1 cm at a 10 cm distance, the N2 long time afterglow (LA-10-2 s) was studied in a large volume reactor (5 liters). At a pressure of 68 Torr, flow rate 0.5 - 1 slpm, the LA at 10-2 s was a jet of dia. 2 cm with densities of N-atoms and N2(X, v > 13) metastable molecules of 1015 and 0.5 1015 cm-3, respectively. By putting a horizontal slit of 50\(mu\)m in front of the dia. 1 mm optical fiber, a light beam of 1 mm dia. was detected across an afterglow tube of 2 cm dia. In an N2 RF plasma at 8 Torr, 1slpm, 100 W, Bessel-typed profiles were recorded for all the radiative bands in the pink afterglow and flat profiles of the N2 580 nm band in the late afterglow. The N2 580 nm band is produced in the late afterglow by N-atoms rebounding on the tube wall, explaining its flat profile. In the pink afterglow, the N2580 nm band is mainly produced by collisions of the N2(X, v > 13) and N2(A) states where N2(A) is destroyed on the tube wall, which explains its Bessel profile. With a small H2 content into N2, the N2(X, v > 13) and N2(A) states in the pink afterglow are destroyed, lowering the N2 580 nm emission that was only produced by the N atoms, yielding a flat profile. A 1 mm radial profile was also obtained with a collimator set on the 1 mm optical fiber and moved along the radial axis of a surface wave (SW) plasma. With a SW plasma, the electric field (E) reaches a maximum value on the tube wall giving high energy to electrons. As a consequence, the Ar metastable atoms produced by high energy electrons and destroyed by low energy electrons (insensitive to E) will show radial profiles of which the shapes were analyzed to determine the metastable excitation (CM) and de-excitation (CM) rates. In Ar SW plasmas at 600MHz, 0.1 Torr, 2 W, it was determined that CM = (1 - 5)10-11 cm3 s-1 and CM = (1 - 3)10-7 cm3 s-1 as for a DC positive column at same electron density: ne = 31010 cm-3. 3D spatial distributions of the intensity of the optical thin ArI 549.6 nm line were measured in DC and SW plasma columns at 150 mTorr inside tubes of 2 cm dia. and 50 cm long. Bessel-type radial distributions were found in the Ar DC column and more rounded profiles in the Ar SW plasmas at 600 - 900 MHz, with hollow shapes at the plasma end.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot 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.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".