Proxima is going with the stellarator approach, which essentially takes the tokamak design and adds a twist to it. The twist is added to help keep the plasma in place, negating the drift that occurs in the donut-shaped tokamak however, it comes with a tradeoff in significantly increasing the complexity of the machine. Given that we have not achieved commercial fusion generation with the much simpler tokamak design, it will be interesting to see whether the added complexity of a stellarator significantly delays commercialization efforts.