Magnetic Effects at the Edge of the Solar System: MHD Instabilities, the de Laval Nozzle Effect, and an Extended Jet
Bibliographic record
Abstract
To model the interaction between the solar wind and the interstellar wind, magnetic fields must be included. Recently, Opher et al. found that by including the solar magnetic field in a three-dimensional high-resolution simulation using the University of Michigan BATS-R-US code, a jet-sheet structure forms beyond the solar wind termination shock. Here we present an even higher resolution three-dimensional case in which the jet extends for 150 AU beyond the termination shock. We discuss the formation of the jet due to a de Laval nozzle effect and its subsequent large-period oscillation due to magnetohydrodynamic (MHD) instabilities. To verify the source of the instability, we also perform a simplified two-dimensional geometry MHD calculation of a plane fluid jet em-bedded in a neutral sheet with the profiles taken from our three-dimensional simulation. We find remarkable agreement with the full three-dimensional evolution. We compare both simulations and the temporal evolution of the jet, showing that the sinuous mode is the dominant mode that develops into a velocity-shear instability with a growth rate of 5; 109 s1 0:027 yr1. As a result, the outer edge of the heliosphere presents remarkable dynamics, such as turbulent flows caused by the motion of the jet. Further study, including neutrals and the tilt of the solar rotation from the magnetic axis, is required before we can definitively address how this outer boundary behaves. Already, however, we can say that the magnetic field effects are a major player in this region, changing our previous notion of how the solar system ends. Subject headinggs: instabilities — interplanetary medium — ISM: kinematics and dynamics — MHD — solar wind — Sun: magnetic fields Online material: color figure, mpeg animation 1.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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 | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".