Enhancement of Plasma Magnetic Field via Radiation Friction at Accessible Laser Intensities

In ultra-high-intensity laser–plasma interactions, electrons lose energy through radiation recoil, an effect known as radiation friction. We found that, surprisingly, this energy loss mechanism can enhance the generation of quasi-static, laser-driven magnetic fields. The effect can be observed at experimentally achievable laser intensities, with the pulse duration playing a key role: as the impact of radiation friction accumulates over time, longer pulses allow the required intensity to be lowered. We performed two PIC simulations—with and without radiation friction—using a 300 fs laser pulse with a peak intensity of 3×10²² W/cm² interacting with a prefilled plasma channel used to guide the laser pulse. Including radiation friction led to a significant increase in the energy of the quasi-static magnetic fields. We investigate the effect through particle tracking and additional test-electron calculations.