Nuclear fusion may always be ten years away, but the technological breakthroughs aiming to get us there are already here—including an imaging technique that vividly shows why fusion is said to harness the energy of the stars.
A recent release from UK-based startup Tokamak Energy presents an unprecedentedly colorful image of a fusion reaction, captured using a high-speed color camera at 16,000 frames per second. The mesmerizing footage is a treat for the eyes, but the different colors each represent valuable information for fusion researchers investigating the efficacy of the reactor.
Plasma is better in colour! Watch one of our latest #plasma pulses in our ST40 tokamak, filmed using our new high-speed colour camera at an incredible 16,000 frames per second.
Each pulse lasts around a fifth of a second. What you’re seeing is mostly visible light from the… pic.twitter.com/jWKmcl0tEx
— Tokamak Energy (@TokamakEnergy) October 15, 2025
For example, the bright pink glow represents the edge of the hydrogen plasma. The green streaks come from lithium ions that trace the path of the plasma around the tokamak, a donut-shaped instrument that confines hot plasma for fusion reactions. The plasma’s core is “too hot to emit visible light,” the company explained, but the other color signals offer invaluable information on how different fusion ingredients interact with one another.
Decoding the colors of fusion
Simply, nuclear fusion combines two lightweight atoms—most often deuterium and tritium, two hydrogen isotopes—to generate massive amounts of energy. Unlike fission, which splits heavy atoms, fusion doesn’t leave behind harmful, radioactive waste.
Fusion would be the ideal alternative to fossil fuels—if we can get it to scale commercially, that is. Although the field has made significant strides over the years, the general understanding is that practical fusion energy is still years away.
Again, fusion’s goal is to replicate stellar energy on Earth, which means fusion experiments involve many extreme conditions that are notoriously difficult to investigate. As with any technology, researchers want to understand how and where things can go wrong—especially when dealing with volatile material like the super-hot plasma confined inside a reactor.
Inching toward better performance
Naturally, physicists have been hard at work finding a workaround. The new footage was part of an investigation into X-point radiator regimes, an approach that seeks to gain better control of plasma flow to “reduce wear without compromising performance,” according to Tokamak Energy.
“The color camera is especially helpful for experiments like these,” said Laura Zhang, a plasma physicist with Tokamak Energy, in the release. “It helps us immediately identify whether the gaseous impurities we’re introducing are radiating at the expected place and whether lithium powders are penetrating to the plasma core.”
“This work is advancing our understanding of plasma behavior as we scale up to energy-producing fusion devices,” added the researchers. “The addition of color imaging is already providing valuable insights into how materials interact within the plasma.”
