Outer radiation belt electron flux and phase space density changes during sheath regions of coronal mass ejections from Van Allen Probes and GPS data
Bibliographic record
Abstract
Turbulent and compressed sheath regions ahead of interplanetary coronal mass ejections are key drivers of dramatic changes in the electron fluxes in the Earth’s outer radiation belt. They are also associated with elevated wave activity in the inner magnetosphere. These changes in electron fluxes can occur on timescales of tens of minutes that are not readily captured by a two-satellite mission such as the Van Allen Probes due to long revisit times. The recently released Global Positioning System (GPS) data set, on the other hand, provides a larger number of measurements at a given location within a given amount of time, owing to the many satellites in the constellation. In our statistical study on the impact of sheath regions on the outer radiation belt, we investigated events in 2012-2018 at timescales of 6 hours (Van Allen Probes data) and 30 minutes (GPS data). The study showed that the flux response to sheaths as reported from Van Allen Probes observations is reproduced by GPS data. We highlight that the shorter timescale allowed by GPS data further confirms that the energy and L-shell dependent flux changes are associated with the sheaths rather than the following ejecta. Additionally, we studied the electron phase space density, which is a key quantity for identifying non-adiabatic electron dynamics. This showed that electrons are effectively accelerated only during geoeffective sheaths (SYM-H < -30 nT). Outer belt losses are common for all sheaths, and the lost electrons are replenished during the early ejecta.
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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) | 0.000 | 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".