On Ganymede’s Magnetic Quadrupolar Strength
Bibliographic record
Abstract
Abstract Ganymede is the only moon in our solar system known to have a large-scale intrinsic magnetic field, likely generated in the moon’s metallic core. Initial analyses of Galileo spacecraft measurements concluded that Ganymede’s intrinsic magnetic field is dominated by a magnetic dipole and that quadrupolar contributions are exceptionally weak. These findings have influenced the development of models for Ganymede’s core dynamo over the past two decades, some concluding that Ganymede’s dynamo is limited to the innermost part of Ganymede’s core. Here, we reassess Ganymede’s internal field contributions based on the magnetic measurements from close Galileo flybys of Ganymede (G1, G2, G7, G8, G28, and G29), adding the recent Juno flyby. We find that presently available data cannot constrain Ganymede’s quadrupole moment, as we demonstrate by constructing models with a range of quadrupole moments, including relative values comparable to those at the Earth. As a consequence, global analysis of available data cannot constrain the spatial limits of Ganymede’s core dynamo. Incorporating ocean induction for a range of Ganymede ocean models indicates that ocean induction may be present, but that available magnetic data cannot discern between end-member cases for Ganymede ocean models.
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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) | 0.002 | 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".