Fusion energy, the same process that powers the Sun and stars, has moved from a theoretical promise to an active engineering race. A handful of private startups, backed by billions in venture capital ...

Fusion power promises to generate large amounts of clean electricity from nearly limitless fuel. This article explains the main approaches and the companies that use them.

Helion says its seventh-generation Polaris machine has heated plasma to 150 million degrees Celsius using deuterium-tritium fuel, a milestone the company is pitching as a turning point in the race to ...