Laboratory generation of strong magnetic fields have been intensively studied because such fields may realize new experimental tools for fundamental studies and support diverse applications. Still, the magnetic strength of familiar examples are relatively weak.
Geomagnetism is 0.3−0.5 gauss (G), and magnetic tomography (MRI) used in hospitals is about 1 tesla (T = 104 G). By contrast, future magnetic fusion and maglev trains will require magnetic fields on the kilotesla (kT = 107 G) order. To date, the highest magnetic fields experimentally observed are on the kT order.
Recently, scientists at Osaka University discovered a novel mechanism called a microtube implosion. Using a supercomputer, they demonstrated the generation of megatesla (MT = 1010G) to order magnetic fields via particle simulations.
Incredibly, this is three ordered of magnitude higher than what has ever been accomplished in a research center. Such high magnetic fields are normal just in celestial bodies like neutron stars and black holes.
Irradiating a tiny plastic microtube one-tenth the thickness of a human hair by ultraintense laser pulses produces hot electrons with temperatures of many billions of degrees. These hot electrons, alongside cool particles, expand into the microtube cavity at velocities moving at the speed of light.
Pre-seeding with a kT-order magnetic field causes the imploding charged particles to infinitesimally twisted because of Lorenz force. Such a unique cylindrical flow collectively delivers remarkably high spin currents of around 1015 ampere/cm2 on the target axis and subsequently, generates ultra-high magnetic fields on the MT order.
The study confirmed that the current laser technology could realize MT-order magnetic fields based on the concept. The present concept for generating MT-order magnetic fields will lead to pioneering fundamental research in numerous areas, including materials science, quantum electrodynamics (QED), and astrophysics, as well as other cutting-edge practical applications.
- M. Murakami et al. Generation of megatesla magnetic fields by intense-laser-driven microtube implosions, Scientific Reports (2020). DOI: 10.1038/s41598-020-73581-4