Comparative Study of Flat and Round Collectors Using a Validated 1D Fluid Probe Model
Bibliographic record
Abstract
Abstract In the literature two different types of Gundestrup‐like probe designs are proposed: design with flat and with round collectors. In this paper we study the influence of different collector shapes of Gundestrup‐like probes on the accuracy of the measurement of the parallel and perpendicular flows. A one dimensional fluid probe model is used for deducing both Mach numbers of the unperturbed flow from the probe data. An analytical expression relates the plasma flow to the measured ion saturation currents collected at the upstream and downstream collecting surfaces of the probe. For flat collectors, the analytical model is validated by comparing it to a two dimensional quasi‐neutral Particle In Cell (PIC) simulation code. An extension of the theoretical model then allows us to study round collectors. We performed an accuracy study which showed that systematic errors are introduced when round collectors are employed for determination of the perpendicular flow which is systematically overestimated. The error can reach more than 70% when the perpendicular flow increases and when the angle of the collecting surface with respect to the magnetic field (θ → 0)is small. The correct analytical expression is applied to experimental data from Gundestrup probe measurements with round collectors on the CASTOR tokamak. The analysis shows that for these measurements the error introduced by using the expression for flat collectors remains negligible, supporting our former use of the model for flat collectors. A new advanced Gundestrup‐like probe design and the motivation for the choice of flat collectors are presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".