China creates “Earth’s second Sun,” a milestone on the road to fusion, the Holy Grail of unlimited energy.

Fusion power has been the fever-dream of scientists, environmentalists, and science fiction writers for almost a century. Fusion produces huge amounts of energy, vastly more than fission (today’s problematic nuclear reactors). It produces no toxic waste, and there’s no chance of a runaway reaction.

For the past few decades, scientists have worked on ways to create sustainable fusion that will provide clean, safe, abundant energy, ending our dependence on fossil fuels and nuclear fission.

Now, scientists working with the Experimental Advanced Superconducting Tokamak (EAST) - aka the “Chinese artificial Sun” - set a new record by super-heating hydrogen plasma to over 100 million degrees F (38 million C), six times hotter than the Sun’s core.

This is a huge milestone in the decades-long pursuit of controlled nuclear fusion, because if we can produce and hold onto hydrogen plasma, we can harness the same clean, practically limitless energy that fuels our Sun, the entire Solar System, and all life on Earth.

At the core of the Sun, intense gravity produces immense pressure and temperature upward of 27 million degrees F (15 million C). This crushes hydrogen atoms until their electrons flee and their nuclei fuse, creating helium: That’s nuclear fusion.

From the core, energy moves to the radiative zone, where it bounces around for up to 1 million years before reaching the convective zone, the upper layer of the Sun’s interior. The temperature here drops to 3.5 million degrees F (2 million C). Large bubbles of hot plasma form a soup of ionized atoms that bubble up to the photosphere.

Human-made fusion reactors don’t have access to the pressures at the Sun’s core - 250 billion atmospheres - so we have to make do with artificial confinement, as with a tokamak reactor. A tokamak has a torus-shaped confinement chamber that uses magnetic fields to confine high-energy plasma.

Super-heating this plasma and keeping it stable creates a self-sustaining fusion reaction. While most tokamak reactors use magnetic coils to keep the hydrogen-fuel plasma torus stable, the Chinese EAST reactor uses the magnetic fields produced via the moving plasma itself. This makes it less stable, but allows physicists to increase heat levels.

Sustaining these incredibly high temperatures is key to achieving controlled nuclear fusion for long enough to harness the energy produced. And - for fusion to be a viable energy source - it also needs to produce more energy than it consumes by sustaining these powerful fields.

This proof-of-concept reactor sets the stage for others, including one in China they expect to start generating power by around 2040, and the 35-nation ITER project, a 10-billion euro ($11.29 billion) fusion reactor under construction in France, scheduled to generate first plasma by 2025. Its aim is creating 500 megawatts of power from just 50 megawatts of input, a tenfold return on energy. With zero radioactive waste.

The age of clean energy shines from just over the horizon - and not a moment too soon!