Figure 1. A microtube implosion is depicted. The cold ion in the inner wall surface is destroyed by the hot electrons produced by the laser. The Larmor gyro motion of the imploding ion and electron is caused by the uniform magnetic fields of the kilotesla order. Strong spin currents of approximately peta-ampere/ cm2 can be produced by the collective motion of charged particles around the central axis. Credit: Masakatsu Murakami.
A research team at Osaka University has demonstrated the generation of megatesla using three-dimensional particle simulations. The magnetic fields of the world are 1–10 billion times stronger than the fields of the earth, and they are only expected to be seen in the vicinity of black holes or neutron stars. This result will help the experiment to achieve magnetic fields in the laboratory.
Scientists have been trying to get the highest magnetic fields in the laboratory since the 19th century. The highest magnetic field observed in the laboratory so far is in the kilotesla order. Microtube implosions are proposed to generate ultrahigh magnetic fields on the MT-order. Irradiating a micron-sized hollow cylinder with ultraintense and ultra short laser pulse creates hot electrons with close to the speed of light. The hot electrons launch a cylindrically symmetric implosion of the inner wall. The trajectory of electrons and ion in opposite directions can be changed by applying a pre-seeded magnetic field parallel to the central axis. Near the target axis, the bent trajectory of ion and electrons form a strong spin current that creates magnetic fields.
One of the team members, Didar Shokov, has extensively conducted three-dimensional simulations using the OCTOPUS at Osaka University's Cybermedia Center. A scaling law has been found relating the performance of the generation of the magnetic fields by MTI and such external parameters as applied laser intensity, laser energy, and target size.
Figure2. The normalized ion density ni/ni0 and the z-component of the magnetic field Bz are seen in a perspective view. The center of the target has a cylindrical cavity with a radius of 5 m and an axis that overlaps the z- axis. The entire domain has a uniformly set seed magnetic field B0 of 6 kT. The four faces of the target are normally irradiated by uniform laser pulse simultaneously, which are characterized by L values of 0.8 m, W cm2 and L values of 50fs. The High Power Laser Science and Engineering was written by Masakatsu Murakami.
Ultrahigh megatesla magnetic fields, which were thought to be impossible to realize on earth, can be achieved using today's laser technology. The Institute of Laser Engineering at Osaka University is currently working on a laser system that will facilitate laboratory experiments using the scaling law and detailed temporal behavior of the magnetic fields in the target.
High Power Laser Science and Engineering is an article about laser scaling for generation of megatesla magnetic fields by microtube implosions. There is a book titled "hpl.2021.46."
The news about the lab trying to achieve megatesla magnetic fields was retrieved from thephys.org on December 9.
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