There is, perhaps, an alternative [to magnetic and inertial fusion]. When liquid undergoes rapid changes in pressure, cavities can form — seemingly from nowhere, but usually around some kind of impurity or imperfection in the fluid. The changing pressure causes this cavity to expand and contract: this is a bubble, and its method of creation is known as cavitation. In particularly violent pressure fields, the bubble can contract so quickly and with so much force that it collapses entirely, producing a shock wave. This phenomenon’s what causes the dramatic pitting on boat propellor and water pumps, where high fluctuating pressures causes bubbles to form and collapse.
But in the controlled environment of a laboratory, the bubbles can do more than cause damage. Way back in 1934, at the University of Cologne, H. Frenzel and H. Schultes turned of the lights in their laboratory, put an ultrasound transducer in a tank of photographic developer fluid, and turned it on. They were hoping to speed up the development process of photographic film — but instead, they noticed dots of light that appeared for a split-second at a time This was the first evidence of a process called sonoluminescene, where the large quantities of energy generated by a collapsing bubble cause light to be emitted. And where there’s light, there’s energy.
Read the article on Gizmodo Australia website.