Highly-accurate, fully-coupled heat transfer-hydrodynamic-electromagnetic simulation for modeling and optimizing laser-driven particle acceleration for laboratory astrophysics

Extreme astrophysical environments – such as those near black holes and neutron stars – are governed by intense electromagnetic fields and relativistic plasmas. Reproducing these conditions in laboratory is now possible by using high-energy-density lasers. However, the lack of accurate, comprehensive models limits our ability to understand, control and optimize these complex processes. To address this, here we present a unified simulation framework that self-consistently couples heat transfer, hydrodynamic and electromagnetic field dynamics, capturing all key physical mechanisms involved in laser-driven particle acceleration via Target Normal Sheath Acceleration (TNSA) and nonlinear Breit–Wheeler (NBW) processes. The model is experimentally validated, achieving predictive accuracy exceeding 95% across multiple benchmark laser facilities. A model-based sensitivity analysis identifies preplasma as the dominant factor influencing particle acceleration, guiding the development of a dual-laser controlled preplasma optimization strategy. To support the experimental implementation of this strategy, the model yields scaling laws that correlate laser parameters to preplasma characteristics. Controlled preplasma conditions are shown to enhance number of positrons by up to four orders of magnitude in TNSA regimes and reduce NBW thresholds to levels accessible with current petawatt lasers, thereby enabling the exploration of relativistic plasma physics relevant to astrophysical environments in the laboratory.