sentences:  For comparison, lead is about 11 g/cm3, so this still represents a considerable amount of compression, notably when one considers the target's interior contained light D-T fuel around 0.1 g/cm3.Ignition is started by a very-short (~10 picoseconds) ultra-high-power (~70 kJ, 4 PW) laser pulse, aimed through a hole in the plasma at the core.The light from this pulse interacts with the cool surrounding fuel, generating a shower of high-energy (3.5 MeV) relativistic electrons that are driven into the fuel.