Scaling of thin wire cylindrical compression with material, diameter, and laser energy after 100 fs Joule surface heating

We present the first systematic experimental validation of return-current-driven cylindrical implosion scaling in micrometer-sized Cu and Al wires irradiated by J-class femtosecond laser pulses. Employing XFEL-based imaging with sub-micrometer spatial and femtosecond temporal resolution, supported by hydrodynamic and particle-in-cell simulations, we reveal how return current density depends precisely on wire diameter, material properties, and incident laser energy. We identify deviations from simple theoretical predictions due to geometrically influenced electron escape dynamics. These results refine and confirm the scaling laws essential for predictive modeling in high-energy-density physics and inertial fusion research.