ITER is designed to address exactly what you have asked. "The ITER thermonuclear fusion reactor has been designed to produce a fusion plasma equivalent to 500

ITER is designed to address exactly what you have asked. "The ITER thermonuclear fusion reactor has been designed to produce a fusion plasma equivalent to 500 megawatts (MW) of thermal output power for around twenty minutes while 50 megawatts of thermal power are injected into the tokamak, resulting in a ten-fold gain of plasma heating power." https://en.wikipedia.org/wiki/ITER https://en.wikipedia.org/wiki/ITER