Why Performance Matters: Accelerating Solar Modulation of Galactic Cosmic Rays with High-Performance Computing

The propagation of Galactic Cosmic Rays (GCRs) within the heliosphere is modeled by the Parker Transport Equation (PTE), which can be numerically solved using a Stochastic Differential Equation (SDE)–Monte Carlo approach. While this method is computationally intensive, the rapid growth of available high-performance computing (HPC) resources now enables its efficient implementation.To fully exploit these advancements, we developed COSMICA, a novel GPU-accelerated code that implements a three-dimensional SDE solver in CUDA/C++, optimized for multi-GPU execution. This allows the simulation of billions of quasi-particle trajectories with unprecedented computational efficiency.In this work, we present COSMICA’s validation against a benchmark heliospheric model, demonstrating runtime reductions exceeding an order of magnitude compared to the benchmark model, while maintaining full consistency with reference flux predictions.