Electron- and proton-scale nested magnetic cavities: Manifestation of kinetic theta-pinch equilibrium in space plasmas
Bibliographic record
Abstract
Magnetic cavities, sometimes referred to as magnetic holes, are ubiquitous in space and astrophysical plasmas characterized by localized regions with depressed magnetic field strength, strongly anisotropic particle distributions, and enhanced plasma pressure. Typical cavity sizes range from fluid to ion and sub-ion kinetic scales, with recent observations also identifying nested cavities that may indicate cross-scale energy cascades. Although heavily investigated in space, magnetic cavities have analogs in laboratory plasmas, the classical theta-pinches. Here, we develop an equilibrium solution of the Vlasov-Maxwell equations in cylindrical coordinates (in similar format to theta-pinch models), to reconstruct the cross-scale profiles of magnetic cavities observed by the four-spacecraft MMS mission. The kinetic model uses input parameters derived from single-spacecraft measurements to successfully reproduce signatures of magnetic cavities from all observing spacecraft. The reconstructed profiles demonstrate that near the electron-scale cavity boundary, the decoupled electron and proton motions generate a radial electric field that contributes to electron vortex formation that has been previously attributed mostly to diamagnetic effects. At larger scales, the diminishing electric field implies that diamagnetic motion is solely responsible for proton vortices.
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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 | 0.000 | 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".