A multiphysics model reveals the potential of controlled preplasma in laser-driven particle acceleration

Understanding and controlling preplasma formation is essential for optimizing laser-driven particle acceleration at high intensities. We have developed a fully coupled multiphysics model that self-consistently integrates heat transfer, hydrodynamic expansion and electromagnetic field evolution in metallic targets. The model captures the full sequence of physical processes from laser absorption to sheath field formation and Target Normal Sheath Acceleration (TNSA). It has been validated against experimental data from multiple high-power laser facilities, covering the terawatt range up to 0.5 PW, achieving predictive accuracy exceeding 95%. Through sensitivity analysis studies, our model identifies preplasma as the dominant factor influencing particles' yield and energy and enables the development of a controlled preplasma methodology based on a tailored laser-pulse sequence. This approach provides quantitative guidance for optimizing experimental conditions and improving the performance of compact, high-brightness particle accelerators, driven by either current or future petawatt-class lasers.