Seasonal and hemispheric asymmetries in the cold ion outflow source region: Swarm and CHAMP observations of F-region polar cap plasma density
Bibliographic record
Abstract
One of the primary mechanisms of loss of Earth’s atmosphere is the persistent “cold” ( ≲ 20 eV) ion outflow that has been observed in the magnetospheric lobes over large volumes with dimensions of order several Earth radii (R). As the main source of this cold ion outflow, the polar cap -region ionosphere and conditions within it have a disproportionate influence on these magnetospheric regions. Using 15 years of measurements of plasma density N made by the Swarm spacecraft constellation and the CHAMP spacecraft within the region of the polar cap above 80{degree sign} Apex magnetic latitude, we report evidence of several types of seasonal asymmetries in polar cap N. Among these, we find that the transition between “winter-like” and “summer-like” polar cap N occurs one week prior to local spring equinox in the Northern Hemisphere (NH), and one week after local spring equinox in the Southern Hemisphere (SH). Thus SH polar cap N lags NH polar cap N by approximately two weeks with respect to local spring and fall equinox in each hemisphere. We show that this lag cannot be explained by differences in solar illumination alone. We also find that overall variation of N in the SH polar cap is greater than overall variation of N in the NH polar cap, except for an approximately two-month period centered on June solstice, and that the greater degree of variability of N in the SH polar cap is partly attributable to differences in illumination of the SH polar cap.
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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 | 0.001 | 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".