Dual scaling for self‐organized critical models of the magnetosphere
Bibliographic record
Abstract
The central plasma sheet is a complex magnetized plasma structure located in the equatorial plane of the magnetotail from where substorms are believed to originate. Dynamically, it may behave like a self‐organized critical (SOC) system, driven by the slow energy input of the solar wind. The power law distributions for the sizes, energies, and durations of substorms that are reflected in observations can be reproduced using such SOC models. However, the expected scale invariance does not seem to hold for all scale ranges and observables. Recent observations of all‐sky auroras have suggested a dual regime, where small and large events scale as different power laws, the smaller events having a steeper slope. On the other hand, scale‐dependent substorm behavior can materialize as a consequence of an energy loading‐unloading cycle. Accordingly, we designed a 2‐D SOC model subject to global deterministic driving and a nonconservative redistribution law. This model can reproduce the coexistence of two scaling regimes, with the second regime appearing as a consequence of the enhanced spatial development of avalanches caused by a higher spatial intermittency in the energy gradients. Thresholded interevent waiting time statistics showed a well‐defined peak with an exponential tail, consistent with observations and the expected dynamics of a loading‐unloading cycle. Finally, we show that the coherency index extracted from the simulations decreases prior to large avalanches, as is in fact observed in auroral arcs. This suggests that the coherency index may be a useful substorm predictor.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 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) | 0.002 | 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".