Blades of Light: Tabletop Technique Will Generate Megatesla Magnetic Fields

Energy

Technological Innovation Website Editorial Team - July 17, 2025

Conceptual illustration of blade implosion of microtubes - sawtooth-shaped internal blades in the cylindrical target induce off-axis charged fluxes, driving strong currents and generating megatesla magnetic fields. [Image: Masakatsu Murakami]

Blades of light

Japanese scientists have devised a technique to generate ultra-strong magnetic fields in the laboratory, approaching the scale of millions of teslas - magnetic fields in the megatesla regime are comparable to those found near strongly magnetized neutron stars or in astrophysical jets.

Just to give you an idea of what this means, the world record for a laboratory-generated magnetic field is 45 tesla .

And it's a compact, laser-driven setup that should facilitate the construction of the necessary laboratory apparatus. The team has dubbed the method "laminate microtube implosion."

It all involves directing very strong laser pulses, each lasting femtoseconds, toward a cylindrical target—the microtube—containing internal sawtooth blades. These blades cause the plasma generated by the laser pulses to rotate asymmetrically, generating circulating currents near the center.

The resulting current self-consistently produces a very strong axial magnetic field, exceeding 500 kiloteslas (0.5 megatesla), approaching the megatesla regime. No external magnetic field is required.

This mechanism contrasts sharply with traditional magnetic compression, which relies on the amplification of an initial magnetic field, an external magnetic field called the seed field. In laminated microtube implosion, the field is generated from scratch, energized exclusively by laser-plasma interactions.

Furthermore, intense magnetic fields can be generated robustly by incorporating structures into the target that break cylindrical symmetry. This process creates a feedback loop in which streams of charged particles—composed of ions and electrons—strengthen the magnetic field, which in turn confines these streams more tightly, further amplifying the field.

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Concepts of the megatesla field generation mechanism (top) and simulations for the eight-blade case (bottom). [Image: Pan/Murakami - 10.1063/5.0275006]

Astrophysics, nuclear and quantum fusion

Once the new magnetic field generator is built, which shouldn't take long, these magnetic fields will have widespread scientific use, particularly in enabling laboratory experiments to study astrophysical phenomena, such as magnetized jets expelled by various types of celestial bodies and even the interior of stars.

Other applications include laser nuclear fusion , facilitating the development of fast proton beam ignition schemes, and quantum electrodynamics, for the study of nonlinear quantum phenomena.

"This approach offers a powerful new way to create and study extreme magnetic fields in a compact format. It provides an experimental bridge between laboratory plasmas and the astrophysical universe," said Professor Masakatsu Murakami of Osaka University.

For experimental teams interested in building the apparatus, the two researchers built a supporting analytical model, demonstrating the fundamental scaling laws and target optimization strategies.

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