Physical Sciences and Mathematics Commons^™

Ultrarelativistic Plasma Shell Collisions In Γ‐Ray Burst Sources: Dimensional Effects On The Final Steady State Magnetic Field, C. H. Jaroschek, H. Lesch, R. A. Treumann

Dartmouth Scholarship

Ultrarelativistic electron-positron plasma shell collisions as an integral part of generic γ-ray burst (GRB) fireball models are studied in the framework of self-consistent three-dimensional particle-in-cell simulations. We compare scenarios at moderately relativistic (γ₀ 10) and ultrarelativistic (γ₀ 100) energies that directly correspond to the regimes of internal and external shell collisions, respectively, in GRB synchrotron emission models. Simulated systems comprise 5 × 10⁸ particles, applying a relativistic, fully electromagnetic, massively parallelized code. It is found that Weibel-generated, steady state magnetic equipartition ratios in external collisions reach up to _B ~ 12%, exceeding the respective internal ratios by …