Simultaneous ground-satellite observations of ELF/VLF emissions generated by a strong magnetospheric compression
Bibliographic record
Abstract
Abstract We report, for the first time, simultaneous nightside observations of very low frequency waves associated with a strong sudden impulse and subsequent magnetospheric compression. On 23 December 2014 at 11:15 UT we observed an intense sudden impulse characterized by an increase of SYM-H amplitude (~ 63 nT), solar wind speed (300–420 km/s), and dynamic pressure (2–6 nPa) with northwards interplanetary magnetic field. Two minutes later, the sub-auroral receiver at Athabasca (ATH, 54.7ºN, 246.7ºE, L = 4.3) detected a chorus-like burst centered at ~ 2.2 kHz from 11:17 to 11:20 UT (03 MLT). At the same time, the nearby Van Allen Probes B (RBSP-B) spacecraft, also in the pre-midnight sector, detected an emission with the same temporal and frequency variations suggesting a conjugate event. One minute before this wave burst, RBSP-B also observed hiss below 1.5 kHz, which was not detected at ATH. Magnetospheric compression can lead to betatron acceleration of plasmasheet electrons and enhancement of temperature anisotropy regulating electron cyclotron instability and whistler-mode generation. However, our observations suggest the generation mechanism between hiss and the discrete emissions differed at the beginning of the compression, in addition to them having different propagation to the ground. The decrease of magnetic curvature in the equatorial plane, caused by strong magnetospheric compression, could be responsible for the hiss being observed first. The subsequent stretching of the field lines, increasing the curvature, likely contributed to the generation of the discrete emissions. This discrete emission with mostly oblique wave angles propagated unducted to the ground, while the more field-aligned hiss did not. These results indicate detailed characteristics of the temporal development of hiss/chorus-like wave generation and propagation in response to the global magnetosphere compression associated with a solar wind pressure pulse. Graphical Abstract
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".