The laser system, developed by Thales of France and whose installation is nearing completion at the Berkeley Lab Laser Accelerator (BELLA), has delivered a petawatt of power in a pulse just 40 femtoseconds long at a pulse rate of one hertz. A petawatt is 1015 watts, a quadrillion watts, and a femtosecond is 10-15 seconds, a quadrillionth of a second. No other laser system has achieved this peak power at this rapid pulse rate.
The BELLA design draws on years of laser plasma accelerator research. Unlike conventional accelerators that use modulated electric fields to accelerate charged particles such as protons and electrons, laser plasma accelerators generate waves of electron density that move through a plasma, using laser beams to either heat and drill through a plume of gas or driving through plasma enclosed in a thin capillary in a crystalline block like sapphire. The waves trap some of the plasma’s free electrons and accelerate them to very high energies within very short lengths, as if the accelerated electrons were surfing on the near-light-speed wave.