A case study of EMIC waves associated with sudden geosynchronous magnetic field changes
Bibliographic record
Abstract
Abstract We present observations of electromagnetic ion cyclotron (EMIC) waves associated with a sudden commencement (SC) on 19 November 2007. In our study, we clearly showed that there was a time delay of ∼10–15 min between the SC onset and the occurrence of EMIC waves at GOES 12 and GOES 10 in the afternoon sector, while the SC‐associated EMIC wave activity observed by GOES 11 in the morning sector started almost immediately after the onset of the SC. This indicates that the EMIC wave source drifts eastward and that magnetospheric compression alone cannot generate EMIC waves without source particles. We suggest that the wave source motion drifting eastward is attributed to the SC‐associated convection electric field, which is slower than the speed of the initial SC disturbance propagating as a fast mode wave. The spectral broadening of EMIC waves for nonlinear wave growth is examined by changing a spatial gradient of the background magnetic field. We have shown that the spectral properties of the observed SC‐associated EMIC waves are in good agreement with the nonlinear theory. In addition, we observed substorm‐associated EMIC wave activity accompanied by a sudden decrease in magnetic field intensity when the satellites were near dusk. By comparing the wave onset times, we confirmed that the substorm‐associated wave source drifted westward.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 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".