The inside of a tokamak--the doughnut-shaped vessel designed to contain a nuclear fusion reaction--presents a special kind of chaos. Hydrogen atoms are smashed together at unfathomably high temperatures, creating a whirling, roiling plasma that's hotter than the surface of the sun. Finding smart ways to control and confine that plasma will be key to unlocking the potential of nuclear fusion, which has been mooted as the clean energy source of the future for decades. At this point, the science underlying fusion seems sound, so what remains is an engineering challenge. "We need to be able to heat this matter up and hold it together for long enough for us to take energy out of it," says Ambrogio Fasoli, director of the Swiss Plasma Center at École Polytechnique Fédérale de Lausanne in Switzerland. That's where DeepMind comes in.

Google's DeepMind AI team has collaborated with physicists from the Swiss Plasma Center at EPFL in Ecublens, Switzerland to develop an AI method to control the plasmas inside a nuclear fusion reactor. The study, published in the scientific journal Nature, furthers nuclear fusion research and could help quicken the arrival of a cheaper, clean, unlimited source of energy. DeepMind has now built a neural network using deep reinforcement learning that is able to manipulate the magnetic coils which are essential to confine the soup of plasma at a temperature that is hundreds of millions of degrees Celsius, even hotter than the sun's core. "This AI algorithm, the reinforcement learning, chose to use the TCV coils in a completely different way, which still more or less generates the same magnetic field. So it was still creating the same plasma as we had expected, but it just used the magnetic cores in a completely different way because it had complete freedom to explore the whole operational space. So people were looking at these experimental results about how the coil currents evolve and they were pretty surprised," said EPFL scientist Federico Felici.

The inside of a tokamak--the doughnut-shaped vessel designed to contain a nuclear fusion reaction--presents a special kind of chaos. Hydrogen atoms are smashed together at unfathomably high temperatures, creating a whirling, roiling plasma that's hotter than the surface of the sun. Finding smart ways to control and confine that plasma will be key to unlocking the potential of nuclear fusion, which has been mooted as the clean energy source of the future for decades. At this point, the science underlying fusion seems sound, so what remains is an engineering challenge. "We need to be able to heat this matter up and hold it together for long enough for us to take energy out of it," says Ambrogio Fasoli, director of the Swiss Plasma Center at École Polytechnique Fédérale de Lausanne in Switzerland.

The inside of a tokamak--the donut-shaped vessel designed to contain a nuclear fusion reaction--presents a special kind of chaos. Hydrogen atoms are smashed together at unfathomably high temperatures, creating a whirling, roiling plasma that's hotter than the surface of the sun. Finding smart ways to control and confine that plasma will be key to unlocking the potential of nuclear fusion, which has been mooted as the clean energy source of the future for decades. At this point, the science underlying fusion seems sound, so what remains is an engineering challenge. "We need to be able to heat this matter up and hold it together for long enough for us to take energy out of it," says Ambrogio Fasoli, director of the Swiss Plasma Center at École Polytechnique Fédérale de Lausanne. That's where DeepMind comes in.