The biggest physics news story of the week (1–7 Feb)


This week has seen a plethora of physics news hit papers and websites, mostly about space. We’ve seen photos of the UK taken by Tim Peake and images from the moon taken by China’s Chang’e 3 lander, unusual cauliflower shapes on Mars and warnings of an asteroid coming quite near to us in March.

However the biggest story this week comes from the Max Planck Institute in Greifswald, north-east Germany. On Wednesday they tested their stellarator with hydrogen for the first time, and managed to produce hydrogen plasma upon the flick of a switch.

This is a significant leap forward in research into nuclear fusion energy – nuclear fusion could one day be the ultimate energy source, producing clean, renewable energy and eliminating fossil-fuel dependency completely.

Their stellarator, a type of nuclear fusion reactor affectionately called Wendelstein 7-X, is an impressive beast that took nearly 10 years to construct, and is the largest in the world. It measures 16 metres in diameter and contains 425 metric tons of superconducting magnets.

The W7-X situated in the lab, with scientists present to show the scale of the stellarator. (Photo: fusenet)

The plan is to use the W7-X to advance our understanding of nuclear fusion, a process that powers stars like our Sun. Nuclear fusion is the binding of two atomic nuclei together, which releases energy in the process. Fusion reactions of lighter elements with small atomic nuclei, like hydrogen and helium, can produce larger elements in a process called nucleosynthesis, and it is this that forms the mass of a star and the energy it radiates.

Inside the W7-X are 70 superconducting magnetic coils, within which lies a plasma vessel. Matter is inserted into the plasma vessel, where it is heated using microwaves and levitated by the magnetic coils until it enters a plasma state. On Wednesday, Chancellor Angela Merkel switched W7-X on, unleashing a two-megawatt pulse of microwave energy, and heating hydrogen gas particles to 80 million degrees until it turned into plasma.

It is only when matter is heated enough to become plasma that atomic nuclei may undergo fusion reactions, theoretically releasing more energy than it took to heat the plasma in the first place.

The W7-X is able to continuously produce plasma for up to thirty minutes, and although cannot capture energy released by the atoms fusing, is a valuable research tool in understanding how we could harness the power of nuclear fusion in the future.

We spoke to Dr Melanie Windridge, an IOP member and former schools lecturer, said she was pleased to hear the W7-X was making significant progress. “It’s great that Wendelstein has produced hydrogen plasma and is beginning the experimental operations”, she said.

“Fusion is the best option we have for long-term future energy, so any experiments that contribute to the fusion knowledge base and get us closer to a working power station are valuable and welcome.”

However, this is not to say that the W7-X is the only big name in fusion research. Stellarators are only one type of nuclear fusion reactors: tokamaks are also commonly used to undertake nuclear fusion experiments, and they differ in the way they manipulate magnetic fields to produce plasma.

The Joint European Torus (JET), located at Culham Centre for Fusion Energy, is the world’s largest and most powerful tokamak, but there are others. (Photo: Flikr)

Windridge works with a start-up called Tokamak Energy, and said that research made possible using tokamak reactors is also making leaps and bounds: “Tokamak Energy are applying new technologies to the tokamak design to reduce the size of the devices and thereby enable us to make them cheaper and faster.

“The team published evidence for the viability of smaller tokamaks last January, and there are also other start-ups in the US working on different machine concepts.

“The start-ups make me hopeful because it shows the scientific and commercial will to achieve fusion.”

The progress of W7-X, although seemingly one of many reactors that are all improving over time, is still an achievement more people should know about. There may be a long way to go before we can finally harness the energy of nuclear fusion, but this week we made some substantial steps in the right direction.

What physics news have you enjoyed reading about this week? Let us know in the comments below.

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Philippa Skett

Philippa Skett

Media Officer at Institute of Physics
Philippa was the IOP's media officer
Philippa Skett

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