Origin of Frequency‐Doubling and Shoulder‐Like Magnetic Pulsations in ULF Waves
Bibliographic record
Abstract
Abstract We present Van Allen Probes observations of a long‐lasting ultralow frequency (ULF) wave event with frequency doubling features in the compressional wave component. The azimuthal magnetic field, on the other hand, shows shoulder‐like pulsations characterized by the presence of two bumps between the crests and troughs within each wave cycle. A wavelet analysis suggests that the shoulder‐like pulsations originate from a secondary peak of the wave power at a frequency of three times the dominant wave frequency. Shoulder‐like pulsations have been observed in many ULF wave events with frequency doubling features, although this phenomenon has never been reported or explained. Here, we propose that these features can be caused by monochromatic oscillations of the magnetic flux tubes in a ballooning‐mirror mode structure. Then, a simple model is developed to reproduce these signatures, which also has the potential to yield uneven bumps in shoulder‐like pulsations depending on the spacecraft location.
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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 | 0.000 | 0.000 |
| 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".