May 2025 monthly summary for the ammarhakim/gkeyll repository focusing on GK Maxwellian stability improvements. Delivered a bug fix to stabilize error calculation for parallel velocity (u_par) in gk_maxwellian_correct by normalizing the error with thermal velocity when u_par is near zero, and corrected a bug in the relative error calculation for larger u_par values. This change enhances numerical stability, reliability of simulations, and overall trust in GK-Maxwellian based results.

March 2025 monthly summary focused on stabilizing core physics kernels and collision logic in two repositories (ammarhakim/gkylcas and ammarhakim/gkeyll). No new user-facing features were released this month; however, two critical bugs were fixed to improve stability and accuracy of simulations: (1) collision gating for non-positive definite vtsq_sr in gkylcas, and (2) BGK cross-collision stability when vtsq_sr is negative at any quadrature point in gkeyll. These fixes reduce numerical instabilities, increase reliability of results, and support downstream validation and decision-making. Key engineering changes include introducing a boolean flag to track non-PD vtsq_sr conditions and conditionally disabling collisions, and updating BGK kernel calculations to disable cross collisions under problematic vtsq_sr conditions. The work enhances robustness, reproducibility, and trust in simulation outputs.

February 2025 monthly summary for ammarhakim/gkylcas focusing on numerical robustness in collision calculations. Implemented stability improvements in the vtsq_sr path to prevent instability when non-positive-definite products occur. The changes harden the simulation against pathological node configurations, improving reliability for production runs.

January 2025 highlights for the ammarhakim/gkeyll repository. Focused on stabilizing gyrokinetic simulations, improving accuracy under high-density conditions, and expanding test coverage to validate more complex configurations. Delivered concrete kernel-level stability fixes, parameter-driven source term tuning, and a new 3x2v test case, driving reliability and business value for high-fidelity plasma modeling.