Ground and satellite observations of the evolution of growth phase auroral arcs
Bibliographic record
Abstract
Auroral substorms are the result of a complex process involving coupling between the solar wind, magnetosphere and ionosphere. In this study, the objective is to understand the processes that precede what is perhaps the most fundamental aspect, the brightening of a preexisting arc at onset. The notion that this brightening provides an indicator of substorm onset remains one of the few aspects of substorms that is not disputed. In order to understand the processes that lead up to onset, auroral arcs that form during substorm growth phases are examined using ground‐based (CANOPUS) data with in situ measurements acquired by the FAST satellite. Four cases have been studied and are discussed in detail here. Consistent with other reports, the data show that the growth phase arcs persist for 30 min or more. During this time, the arcs often show little or no fluctuations, although a gradual intensification is clear in the ground‐based optical measurements. Two important results emerge from this study. First, FAST observations show that growth phase arcs develop within the region of proton precipitation but generally poleward of most intense precipitation, a topic that has been addressed (and disputed) using ground‐based observations of luminosity, a secondary effect. Second, we show that FAST observations before the growth phase arc is established show scattered plasma sheet electrons with no significant structure. However, once the growth phase is well developed, FAST confirms that the arcs are excited via inverted V precipitation, implying that an inverted V potential drop gradually develops in conjunction with the evolution of the growth phase.
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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 | 0.001 |
| 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) | 0.001 | 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".