Watch the scientists accidentally explode their lab with the most powerful internal magnetic field ever

Earlier this year, researchers at the University of Tokyo accidentally created the most powerful controllable magnetic field in history and blew the doors of their lab.

As detailed in an article recently published in the Review of scientific instrumentsThe researchers produced the magnetic field to test the material properties of a new generator system. They expected to achieve maximum magnetic field strengths of about 700 Tesla, but the machine instead produced a peak of 1200 Tesla. (For the sake of comparison, a refrigerator magnet has about 0.01 Tesla)

It is the most powerful magnetic field ever generated in a controlled indoor environment, but it is not the most powerful magnetic field produced in history. This honor belongs to some Russian researchers who created a magnetic field of 2,800 Tesla in 2001.

In both Japanese and Russian experiments, magnetic fields were generated using a technique called electromagnetic flux compression. This technique causes a brief increase in the strength of the magnetic field by compressing it quickly to a smaller size. This technique has been around since the 1940s, but at first it used large amounts of TNT to generate an explosion powerful enough to compress the magnetic field. The disadvantage of this technique was that it could only be done once the explosion had destroyed the equipment. In addition, it was difficult to reproduce and control the explosion.

Instead of using TNT to generate their magnetic field, Japanese researchers have injected a huge amount of energy – 3.2 megajoules – into the generator to cause the rapid compression of a weak magnetic field produced by a small spool at a speed of about 20,000 miles per hour. This involves feeding 4 million amps of current through the generator, several thousand times more than a flash. When this coil is compressed as small as possible, it bounces. This produces a powerful shock wave that has destroyed the coil and much of the generator.

To protect themselves from the shock wave, Japanese researchers built an iron cage for the generator. However, they only built it to withstand around 700 Tesla, so the shock wave of the 1200 Tesla eventually expelled the door from the speaker.

"I did not expect it to be so high," said Shojiro Takeyama, a physicist at Tokyo University. "Next time, I'll do [the enclosure] stronger."

According to the researchers, this experiment not only provides insight into how different materials respond to powerful magnetic fields, but can also find applications in the quest for fusion energy. Many models of leading fusion reactors require the application of powerful magnetic fields in the order of thousands of Tesla over short periods, a requirement that researchers have described as "very similar" to what they produced. .

Read more: We were promised fusion energy

After making some adjustments to the generator and rebuilding the iron cage, the researchers plan to pump 5 megajoules of energy into the generator next time, about 1,500 Tesla.

"Only 40 years ago, magnetic fields in the order of 1000 Tesla were reported only in extremely complex and sometimes unreliable systems, without sophisticated controls," the researchers concluded in their report. "Therefore, it can be said without a doubt that current results represent the beginning of a new era in the research and use of ultra-high magnetic fields for solid state studies and experiments related to plasma fusion. "