Large‐scale vortex dynamics in the evening and midnight auroral zone: Observations and simulations
Bibliographic record
Abstract
We use Canadian Auroral Network for the OPEN Program Unified Study All‐Sky Imager (ASI) and Meridional Scanning Photometer (MSP) data as the basis for a study of the dynamics of large‐scale (hundreds of kilometers) auroral vortices. We consider 28 events corresponding to a range of auroral activity levels. Three of these are presented in detail, one corresponding to growth phase, one to pseudo‐breakup and one to expansive phase onset. We show that vortex formation starts from a discrete arc with half thickness δ of the order of 20 km. This arc intensifies near the poleward boundary of enhanced proton aurora, as seen in the Hydrogen β (Hβ) MSP data and becomes azimuthally structured. This structuring is in the form of vortices with wavelength of the order of ∼ 2πδ. The vortices intensify and extend radially, leading to broadening of the initial arc. While the sizes and growth rates of the vortices vary, the overall scenario of vortex evolution is similar for all of the events. Structures that develop during the growth phase saturate at latitudes matching the poleward boundary of Hβ emissions and pseudo‐breakup structures saturate further poleward. Expansive phase onset vortices expand poleward in a similar fashion, but we do not observe any saturation stage, presumably due to limitations imposed by the ASI field of view. We present results of shear flow ballooning vortex modeling in which we used initial conditions and parameters consistent with our observations. On the basis of our model results, we speculate that all of these experimentally observed vortices are the result of shear flow ballooning instability in the hot proton region in the near‐Earth plasma sheet.
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 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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| 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".