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Record W3095771048

Dynamics of runaway electrons in tokamak plasmas

2015· preprint· en· W3095771048 on OpenAlex
Emelie Nilsson

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

aboutThe title or abstract carries a Canadian signal from the geographic lexicon.
no affNo Canadian affiliation: this work is invisible to an affiliation-only frame.
No Canadian affiliation. An affiliation-only frame, the usual design, would never have seen this work. It is one of the works that make the case for inverting the frame.

Bibliographic record

VenueINRIA a CCSD electronic archive server · 2015
Typepreprint
Languageen
FieldPhysics and Astronomy
TopicMagnetic confinement fusion research
Canadian institutionsnot available
Fundersnot available
KeywordsPhysicsTokamakElectronPlasmaPopulationAtomic physicsContext (archaeology)Electric fieldNuclear physicsQuantum mechanics
DOInot available

Abstract

fetched live from OpenAlex

One of the key features of a plasma is that the collisional friction resulting from Coulomb interactions decreases with the electron velocity. Therefore, in the presence of a parallel electric field larger than a critical value, electrons with sufficient velocity will be continuously accelerated. These so-called runaway electrons may reach energies on the order of several MeVs and cause serious damage to plasma facing components in ITER - the next large-scale tokamak. The runaway population may be multiplied through knock-on collisions, where an existing runaway electron can transfer a significant fraction of its energy to a secondary electron nearly at rest, while remaining in the runaway region. Understanding of the runaway electron formation processes is crucial in order to develop ways to mitigate them. In this context, modelling of runaway electron dynamics is performed using the 3-D linearized relativistic bounce-averaged electron Fokker-Planck solver LUKE, with a particular emphasis on knock-on collisions of fast electrons on thermal ones, which can lead to an avalanche of relativistic electrons. The theory of bounce-averaged knock-on collisions is derived, and the corresponding operator is implemented in the kinetic solver LUKE. The dependencies of the runaway electron growth rate on the electric field strength, density, temperature and magnetic configuration is investigated, in order to identify the relative importance between primary and secondary runaway generation, the latter resulting from the avalanche process. It is shown that avalanches of runaway electrons can be important even in non-disruptive regimes and this effect may become dominant in the build-up of the highly relativistic electron tail. Owing to their high magnetization, most of the knock-on electrons are born into the magnetic trapping domain in momentum space, which leads to a reduction of the runaway population off the magnetic axis. This accumulates the runaway electrons near the magnetic axis. The dynamics of the trapped electrons in the framework of runaway electron generation is investigated. Finally, the runaway electron formation in Ohmic discharges performed in the Tore Supra and COMPASS tokamaks is modelled with the LUKE code, using global plasma parameters such as parallel electric field and the toroidal MHD equilibrium calculated with the fast integrated modelling code, METIS. Details of the fast electron velocity distribution function are provided as well as quantitative comparison with non-thermal bremsstrahlung for the Tore Supra tokamak.

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.

Full frame distilled prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow), Research integrity, Insufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Theoretical or conceptual · Consensus signal: Theoretical or conceptual
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.186
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0010.002
Research integrity0.0000.002
Insufficient payload (model declined to judge)0.0220.000

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.

Opus teacher head0.010
GPT teacher head0.261
Teacher spread0.251 · 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