Energy is delivered to the surface of a tiny hollow sphere (a few millimeters in diameter) of fusion fuel (the target). The blue arrows represent the driver energy delivered to the target—this is the laser light, x-ray radiation or particle beams that heat the outer yellow shell. Stage 2: Orange arrows indicate the ablation of the outer shell that pushes the inner shell towards the center. The compression of the fusion fuel to very high density increases the potential fusion reaction rate. Stage 3: The central low-density region, comprising a small percentage of the fuel, is heated to fusion temperatures. The light blue arrows represent the energy transported to the center to heat the hot spot. This initiates the fusion burn. Stage 4: An outwardly propagating fusion burn wave triggers the fusion of a significant fraction of the remaining fuel during the brief period before the pellet explodes/disassembles. Steady power production is achieved through rapid, repetitive fusion micro-explosions of this kind.