Beam Pointing Instability in High-Repetition-Rate Laser Filaments: A Comprehensive Numerical Modeling Approach

Previous studies on the multi-physics coupling of filament jitter often lack systematic and detailed modeling methodologies. To uncover the underlying mechanism, we developed a comprehensive multi-physics numerical framework.

By deeply coupling the nonlinear Schrödinger equation, plasma evolution, and thermal-fluid equations, we quantitatively model the laser-induced refractive index fluctuations. Incorporating Kolmogorov phase screens and ray-tracing, we successfully reproduced the beam pointing jitters across various repetition rates. Our simulations demonstrate excellent agreement with experiments, revealing that cumulative fluid-dynamic effects from post-filamentation energy deposition fundamentally govern this pointing instability.