Ionospheric ions in the magnetosphere: Important at large and small scales
Bibliographic record
Abstract
Cold (eV) ions of ionospheric origin dominate the number density of most of the volume of the magnetosphere during most of the time. Supersonic flows of cold positive ions are common and can cause a negatively charged wake behind a positively charged spacecraft. The associated induced electric field can be observed and can be used to study the cold ions. We present observations from the Cluster and MMS spacecraft showing how a charged satellite, and also individual charged wire booms of an electric field instrument, can be used to investigate cold ion populations. Ionospheric ions affect large scales, including the Alfvén velocity and thus energy transport with waves and the magnetic reconnection rate. These ions also affect small-scale kinetic plasma physics, including the Hall physics and wave instabilities associated with magnetic reconnection. Concerning large scales, we summarize observations from several spacecraft and show that a typical total outflow rate of ionospheric ions is 1026 ions/s and that many of these ions stay cold also after a long time in the magnetosphere. Concerning small scales, we show examples of how cold ions modify the Hall physics of thin current sheets, including magnetic reconnection separatrices. On small kinetic scales the cold ions introduce a new length-scale, a gyro radius between the gyro radii of hot (keV) ions and electrons. The Hall currents carried by electrons can be partially cancelled by the cold ions when electrons and the magnetized cold ions ExB drift together. Also, close to a reconnection X-line an additional diffusion region can be formed (regions associated with hot and cold ions, and with electrons, total of three).
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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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".