Innovation Winter 2024.25

The first of these components is creating a plasma target that holds in heat. “The types of plasmas that we need have a structure to them,” explained Donaldson. “They have a very specific magnetic field, and forming the shape and structure holds in the heat.” General Fusion has completed over 200,000 plasma shots over the course of the company’s history. Years of work went into creating focused prototypes that increased energy confinement time, a term for the amount of time that particles can be contained within the plasma. The company’s focus on plasma allows for slower compression of the medium, which helps increase the reliability of its mechanical systems. The second component is the liquid cavity: the buffer of liquid lithium that surrounds the plasma and helps breed tritium. “As a company, we really learned how to work with liquid metal,” said Donaldson. “Where do you need your seals? How are you going to create a vacuum behind that seal? A lot of the tricks are required for doing our technology.” General Fusion completed its first major liquid compression tests in 2012 and have created further prototypes that scale compression system, which needs to be precise enough to manipulate the plasma to target temperatures. “Everybody would always ask us, ‘You're going to create fusion with pistons – doesn't the timing need to be really precise, and don't you need to control that?’” said Donaldson. Some of their earliest prototypes from the early 2010s focused solely on the compression component, which allowed General Fusion to demonstrate it had the timing and precision necessary to collapse the liquid lithium cavity with a shock wave. Large-scale machine targeted After establishing these subsystem prototypes in the first decade, the company is now creating larger integrated systems, first fitting plasma to a commercial machine. The final component is the

Mike Donaldson, a vice president at General Fusion, shows a 2024 prototype at one-fifth the scale of their expected scientific breakeven machine.

Drillwell

Innovation Winter 2024/25

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