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11-06/07 :: June/July 2011
nanotimes News in Brief World Record: The Highest Magnetic Fields are Created in Dresden
On June 22, 2011, the German Helmholtz- Zentrum Dresden-Rossendorf set a new world record for magnetic fields with 91.4 teslas. To reach this record, Sergei Zherlitsyn and his colleagues at the High Magnetic Field Laboratory Dresden (HLD) developed a coil weighing about 200 kilograms in which electric current create the giant magnetic field – for a period of a few milliseconds. The coil survived the experiment unscathed.
“With this record, we’re not really that in- terested in reaching top field values, but instead in using it for research in materials science,” explains Joachim Wosnitza, the HLD’s Director. The scientists are actually proud of being the first user lab worldwide to make such high magnetic fields availa- ble for research. The more powerful a magnetic field is, the more precisely the scientists can examine those substances which are used for innovative electronic components or for so-called superconductors which conduct electricity without any resistance. Such high magnetic fields are generated by passing an electric current through a copper coil.
In order to examine as closely as possible the electric charge in the materials of tomorrow, researchers need higher magnetic fields with, for example, 90 or 100 teslas. “At 100 teslas, though, the Lorentz force inside the copper would generate a pressure which equals 40,000 times the air pressure at sea level,” cal- culates Joachim Wosnitza. These forces would tear copper apart like an explosion. That is why researchers use specific copper alloys which can withstand ten thousand times the atmospheric pressure. They then add a corset made from a special fiber that is typically used for bulletproof vests and which holds the alloy together from the outside. The HZDR technicians wind six of these special wires with corsets into a coil that has a hollow space of 16 millimeters at its center. This permits the generation of 50 teslas within this special coil when a brief but powerful electric pulse flashes through the copper – a process that is over after a mere 0.02 seconds.
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