Towards the realization of megatesla magnetic fields in the laboratory – sciencedaily
Recently, a research team from Osaka University successfully demonstrated the generation of megaatesla (MT) order magnetic fields via three-dimensional particle simulations on the laser-matter interaction. The strength of MT magnetic fields is 1 to 10 billion times stronger than that of geomagnetism (0.3 to 0.5 G), and these fields should only be observed in close proximity to celestial bodies such as stars at neutrons or black holes. This result should facilitate an ambitious experiment to achieve magnetic fields of order MT in the laboratory, which is currently underway.
Since 19e century, scientists strove to achieve the highest magnetic fields in the laboratory. To date, the highest magnetic field observed in the laboratory is of the order of kilotesla (kT). In 2020, Osaka University’s Masakatsu Murakami proposed a new scheme called microtube implosions (MTI) to generate ultra-high magnetic fields on the MT order. Irradiation of a micron-sized hollow cylinder with ultra-intense, ultrashort laser pulses generates hot electrons with speeds close to the speed of light. These hot electrons initiate a cylindrically symmetrical implosion of ions from the inner wall towards the central axis. An applied pre-seeded magnetic field of the order of kilotesla, parallel to the central axis, curves the trajectories of ions and electrons in opposite directions due to the Lorentz force. Near the target axis, these curved trajectories of ions and electrons collectively form a strong spin current which generates magnetic fields of order MT.
In this study, one of the team members, Didar Shokov, conducted numerous three-dimensional simulations using the “OCTOPUS” supercomputer at the Cybermedia Center at Osaka University. As a result, a separate scaling law was found regarding the performance of generating magnetic fields by MTI and external parameters such as applied laser intensity, laser energy and target size.
“Our simulation showed that megatesla’s ultra-high magnetic fields, which were thought to be impossible to achieve on earth, can be achieved using today’s laser technology. The law of scale and the Detailed temporal behavior of the magnetic fields in the target should facilitate laboratory experiments using the Peta-watt ‘LFEX’ laser system at the Osaka University Institute of Laser Engineering, which are currently underway, ”said Murakami.
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