For the first time, scientists have released high-resolution footage from inside a fusion reactor, capturing plasma at an incredible 20 million degrees.
The video, recorded by British company Tokamak Energy, shows glowing ribbons of plasma swirling inside its compact ST40 spherical tokamak. Filmed at 16,000 frames per second, it is the most detailed look ever captured of fusion plasma in motion.
What the footage shows is more than just a colorful light show. As deuterium gas ionizes and gets trapped in the magnetic field, it glows pink. Cooler areas flash red when fuel pellets streak through, while lithium, used as a wall coating and tracer, emits a greenish-yellow light, tracing the magnetic field lines like a luminous web.
Each color represents a specific element, temperature zone, or reaction. For fusion scientists, this is like moving from static graphs to a live video feed. The images reveal turbulence, wave patterns, and plasma motion that were previously visible only through simulations.
The footage was made possible by LEAPS, a 52 million dollar collaboration between the US Department of Energy and the UK's Department for Energy Security and Net Zero. The project aims to make fusion reactors more durable and controllable by studying how plasma interacts with reactor walls. The ST40 has received upgrades such as lithium coatings to absorb impurities, molybdenum tiles to resist erosion, and advanced imaging tools like the high-speed color camera.
Fusion reactors often fail not because they lack heat, but because unstable plasma edges damage internal walls. With these recordings, scientists can now see those critical zones frame by frame, identifying where heat bursts form and how to control them.
The ST40 is also testing a method called X-Point Radiator mode, which cools outer plasma just enough to radiate heat before it hits the walls. Before this, fine-tuning that balance was largely guesswork. Now, researchers can watch the process unfold in real time.
This breakthrough offers a major step in the race for practical fusion power. Compact reactors like the ST40 may provide a path toward affordable, scalable clean energy.
As Tokamak Energy researcher Max Hogg said, "For decades, we've only seen fusion through data. Now, we can actually watch it happen."
It's a rare glimpse into the heart of a machine that could one day power the world with the same energy that fuels the stars.