Dependence of the Interplanetary Magnetic Field on Heliocentric Distance at 0.3–1.7 AU: A Six‐Spacecraft Study
Bibliographic record
Abstract
Abstract We use magnetometer data taken simultaneously by MESSENGER, VEX, STEREO and ACE to characterize the variation of the interplanetary magnetic field (IMF) with heliocentric distance, , for 1 AU. Power law fits () to the individual IMF components and magnitude indicate that, on average, the IMF is more tightly wound and its strength decreases less rapidly with than the Parker spiral prediction. During Solar Cycle 24, temporal changes in were insignificant, but changes in amplitude, , were correlated with sunspot number, up to sunspot number 84. MAVEN data taken at 1.4–1.7 AU since late 2014 broadly confirm and extend these results in space and time. Our study demonstrates the importance of simultaneous observations from multiple spacecraft to separate heliocentric distance and temporal variations in the IMF and provides a modern benchmark for comparison with data from the Parker Solar Probe Mission.
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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 | 0.000 |
| 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".