A Lab Blast at 800,000 Degrees Tests a Sun Several Million Degrees Hot

A team at the China Institute of Atomic Energy says it has recreated in the laboratory a small magnetic explosion of the kind that may heat the Sun's outer atmosphere, according to a New Scientist report published on October 22, 2026. ^[1]

The result rests on a paper in Physical Review Letters, which we have not seen. What follows comes from New Scientist's account of it, and the claim is still to be tested by other physicists.

A reversal of common sense

Move away from a fire and you get cooler. The Sun does the opposite. Its visible surface is hot, but the corona, the thin halo of plasma around it that shows during a total eclipse, is much hotter still. The report puts the corona at several million degrees. ^[1]

For decades this has been one of the standing puzzles of solar physics. Energy has to travel through the cooler layer to reach the hotter one, and the heat has to be deposited somewhere, somehow, against every intuition.

The leading candidate is the nanoflare. A solar flare is a sudden release of magnetic energy, the sort that can throw out radiation and charged particles. A nanoflare is the same idea scaled far down, a brief snap as tangled magnetic field lines rearrange. One of them is too small to see. The hypothesis is that vast numbers of them, firing all the time, add up to the heat the corona holds.

What the team did

The team, led by Wei Sun, fired four powerful lasers at a small plastic target. The blast made a plasma, a gas so hot that its atoms are stripped into charged particles, about two millimetres across. ^[1]

It is not a copy of the corona. The report describes it as behaving analogously. ^[1]

Then came the comparison that makes the experiment useful. The researchers ran it twice, once with a flat target and once with a target whose surface was wavy. In the wavy case, the plasma became unstable, its magnetic fields rearranged, and a nanoflare was produced. With the flat target, no nanoflare appeared. ^[1]

The temperatures differ too. In the nanoflare run the plasma reached 799,726°C, nearly double what the flat-target run reached. ^[1]

Two features help the case. The report says the experiment's parameters matched those seen in regions of the Sun where cooler blobs of plasma, known as coronal rain, fall through the corona. The team also ran a computer simulation, which supported its reading of the results. ^[1]

Sun said the same sequence of instability, nanoflares and heating could happen on the Sun. ^[1]

Why a bench matters

Until now, much of the argument over nanoflares has lived in models and in telescope images that cannot resolve events this small. A model shows what a set of assumptions would do. It cannot show that nature obeys the assumptions.

A laboratory plasma you can change on purpose is a different kind of evidence. The team can swap a flat surface for a wavy one and watch whether the magnetic fields tear and the plasma heats. That is a controlled test of a mechanism, and the corona has rarely allowed one. Nobody can reach in and adjust the Sun.

There is a plain gap, though, that the numbers make visible. The lab plasma reached about 800,000 degrees, and the corona runs to several million. The experiment shows a heating mechanism working at small scale. It does not show that the mechanism reaches coronal temperatures, and it was not built to.

The limits

Rony Keppens of KU Leuven in Belgium, who was not part of the work, told New Scientist that the simulations support the team's interpretation. He also said coronal rain blobs could produce the kinds of instabilities seen in the lab. ^[1]

But he said the experiment does not settle the coronal-heating puzzle, because other plasma processes, including some kinds of waves, could contribute as well. ^[1]

That caution matters because the corona has never lacked explanations. Waves carrying energy up from below and nanoflares are rival and possibly partner candidates. A result that favours one mechanism's plausibility does not remove the other. It is entirely possible that the Sun uses both.

The paper's own details also remain to be examined. How many runs the team performed, how repeatable the instability was, and how large the measurement uncertainties are would all show in the full paper and its supplementary material. The coverage so far does not report them.

What comes next

Sun said the team wants to create more three-dimensional plasmas, improve its diagnostic techniques and compare its measurements more directly with telescope observations. ^[1]

The last step is the one to watch. A flat or wavy target in a vacuum chamber tells you what is possible. A direct match against solar telescope data would begin to tell you what is actually happening up there.

If the lab and the Sun keep agreeing as the experiments get harder to fudge, nanoflares will have moved from the most attractive idea about the corona to something nearer a measured fact. Until then it is a good bench result and a good reason for other groups to build their own.