sentences:  This corresponds to a "fusion gain" —the ratio of input laser power to output fusion power— of about 5.If one uses the baseline assumptions for the current HiPER design, the two lasers (driver and heater) produce about 270 kJ in total, yet generate 25 to 30 MJ, a gain of about 100.Considering a variety of losses, the actual gain is predicted to be around 72.