Electrostatic field and ion temperature drop in thin current sheets: A theory
Bibliographic record
Abstract
The observational evidence presented by Liang et al. (2009) showed that a neutral sheet–pointing electrostatic field frequently arises in the late growth‐phase current sheet in the magnetotail. In this paper, we elaborate on the suggestion that this electric field is associated with the thinning of the current sheet to the ion scale at which the electron and ion current sheets begin to separate. The attendant effect of a decreasing ion temperature, also interpreted in terms of a thinning current sheet, suggests that a cold plasma population is involved. We review existing theories of “charged” Harris sheet that can produce electrostatic fields and show that they cannot explain the observations for various reasons. A particular problem is the over shielding of the electrostatic field by the cold population embedding the current sheet. We argue that this problem stems from not treating the cold plasma as a separate population from the hot plasma forming the thin current sheet (TCS). We show that if the cold population is treated as external to the TCS and behaving in a largely MHD manner, the resultant solution yields an electrostatic field and ion temperature drop consistent with the observations.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.001 | 0.003 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".