Particle acceleration in a relativistic shock in inhomogeneous media
Bibliographic record
Abstract
It is known that the maximum energy of Cosmic Rays (CRs) reaches to around $10^{20}$ eV. One of the candidates of the acceleration mechanism of these highest-energy CRs is shock acceleration in a relativistic shock. However, it is also known that in a relativistic shock, particles cannot go back and forth around the shock many times, because there is almost no difference between the shock velocity and the particle velocity. In this work, we consider density fluctuations in the shock upstream region. The interaction of density fluctuations and a relativistic shock drives the turbulence in the shock downstream region. This turbulence could change their direction of particle motion. We carried out the MagnetoHydroDynamic (MHD) simulations and test-particle simulations to check this mechanism can accelerate the CRs. We found that particles can cross the shock front many times thanks to scattering by the downstream region. In addition, the amplitude of the density fluctuation is an important parameter to determine the acceleration efficiency. We revealed a condition where particles can cross the shock many times.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 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) | 0.002 | 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".