Not long ago, a team of scientists from Osaka University, Japan, successfully demonstrated that the task of creating the strongest magnetic fields, the strength of which is measured in millions of Tesla, is feasible in the laboratory at the current level of technology. Magnetic fields at the megaTesla (MT) level are 1-10 billion times stronger than the Earth's magnetism. Previously it was thought that magnetic fields of this level could only be observed in the immediate vicinity of such cosmic objects as neutron stars and black holes, and could not be obtained on Earth by any artificial means. But the results of work by Japanese researchers, who have carried out sophisticated mathematical modelling of the interaction between matter and laser light, have shown the possibility of an ambitious experiment, preparations for which are already under way.
Ever since the 19th century, scientists have been trying to create the strongest magnetic fields. Currently, the upper limit for the strength of an artificial magnetic field is a magnetic field of thousands of Tesla, kiloTesla.
In 2020, Masakatsu Murakami, a scientist at Osaka University, proposed an entirely new method called MTI (microtube implosions) to produce an even stronger magnetic field. The method involves using a tiny micron-sized hollow cylinder made of a special material, which is irradiated at specified intervals with high-intensity, ultra-short pulses of laser light.
When light interacts with the material of the cylinder, super-hot electrons moving at a speed close to the speed of light are produced, which cause a phenomenon of cylindrical symmetric implosion of matter ions of the cylinder walls in the direction of the central axis. To this whole system, an external magnetic field of kiloTesla level is applied, which bends trajectories of ions and electrons in opposite directions due to Lorentz forces. And as a result, a flux of ions and electrons swirls around the axis of the cylinder to form the strongest electric current, which produces a megaTesla-level magnetic field.
Not long ago, scientists used the OCTOPUS supercomputer to simulate the magnetic field generation process described above. After going through a host of different combinations, the supercomputer found a near-ideal scenario of laser light intensity, pulse energy, geometric dimensions of the cylinder and other parameters that would produce a megaTesla-level magnetic field inside the cylinder.
"Masakatsu Murakami says, "Our simulations have shown that superstrong magnetic fields, previously thought impossible to produce on Earth, can well be created in the laboratory using modern laser technology", "Our results will greatly facilitate the experiments that will use the petawatt laser LFEX and preparations for which are already underway".
