Electrodynamics of Magnetars. IV. Self‐Consistent Model of the Inner Accelerator with Implications for Pulsed Radio Emission
Bibliographic record
Abstract
We consider the voltage structure in the open-field circuit and outer magnetosphere of a magnetar. The standard polar cap model for radio pulsars is modified significantly when the polar magnetic field exceeds 1.8 × 10 14 G. Then a surface gap is effectively screened, because resonantly scattered X-rays can convert almost instantaneously to electron-positron pairs. We point out a second possible voltage distribution, in which backflowing charges spawn just enough pairs to compensate the gradient in the corotation charge density. We also examine the gap structure when the magnetic field is somewhat weaker and deduce a voltage 10-30 times larger over a range of surface temperatures. We examine carefully how the flow of charge back to the star above the gap depends on the magnitude of the current, on the curvature of the magnetic field lines, and on resonant drag. The rates of different channels of pair creation are determined self-consistently, including the nonresonant scattering of X-rays and collisions between gamma rays and X-rays. Both circuit solutions are subject to a two-stream instability due to a spatially extended return charge flow. The voltage is high enough to sustain the radio output of strongly magnetic pulsars, but not of the two radio magnetars with active magnetospheres, unless the gap is also present on the closed magnetic field lines. Several properties of the radio magnetars—their rapid variability, broad pulses, and unusually hard radio spectra—are consistent with a third possibility, that the current in the outer magnetosphere is strongly variable and a very high rate of pair creation is sustained by a turbulent cascade.
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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 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| 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".