Modeling plasma contact with the main vessel walls of a divertor tokamak
Bibliographic record
Abstract
Simple, analytic models are developed to estimate the plasma particle fluxes to the main chamber walls of a divertor tokamak in terms of assumed values of the cross-field transport coefficients, D⊥, v⊥, and of the wall–gap size. The wall–gap size is the cross-field width of the gap between the last closed flux surface, LCFS, defined by magnetic (divertor) separatrix and the wall of the main chamber, the “wall-limiter.” The neutrals recycling from the wall may be ionized at, or inboard of, the LCFS—which is a key feature of the so-called “simple SOL” and which is referred to here as the pure transport case. On the other hand, the neutrals may be ionized within the scrape-off layer, SOL, in the main chamber, with the ions returning to the wall—referred to here as the SOL ionization case. SOL ionization gives rise to a radial flux amplification effect, in the sense that the plasma flux to the walls is larger than for the “simple SOL”—all else held equal, including the separatrix density, wall–gap, and the transport coefficients. The amplification factor is found to be only modest, however, up to ∼2x. Primarily, plasma–wall contact is therefore just simply a function of cross-field plasma transport, which is strongly anomalous in the SOL, probably due to turbulence, and possibly intermittent, large-event activity in the outer regions. The experimental database for D⊥SOL, v⊥SOL is weak, particularly for the far SOL, a situation calling for increased experimental and theoretical effort.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.010 | 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 teacher head, 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".