Laboratory-produced quasi-static magnetic field with astronomical strength driven by ultra-high intensity lasers

Abstract

Laboratory-produced strong magnetic fields have attracted many fields of research, from astrophysics to material science, and magnetic fields of up to 100 Tesla (T) are now available using pulsed magnets. Recent progress in high-power laser technology has provided new possibilities to produce much higher magnetic fields of the order of kilo-Tesla by laser-driven schemes. Here we present our new approach of producing strong magnetic fields with values far exceeding all known laboratory records by using a special micro-coil and a high-power laser. As theoretically shown in [Phys. Rev. E 91, 043107 (2015)], our scheme is based on the strong solenoidal current driven by laser. A laser pulse is tightly focused on the edge of a single-turn coil with the diameter of hundreds of microns, where the light intensity reaches 10¹⁹ W/cm² and a lot of electrons are eliminated out of the coil by the ponderomotive force of the laser light. A strong solenoidal current continues to flow in the coil during this process in order to neutralize the surface charge in the laser interaction region and generates a strong magnetic field by Biot-Savart law. The estimated peak field amplitude exceeds 10 kT, which is almost comparable to the magnetic fields near the surface of white dwarfs and neutron stars. Another unique feature of this scheme is the ability to form either parallel or anti-parallel field structure selectively by optimizing the shape of the coil. We succeeded in the first demonstration of this scheme using the LFEX laser facility at the Institute of Laser Engineering of Osaka University, and the experimental results will be discussed in the presentation. A 10-kT parallel and anti-parallel magnetic fields could have a profound impact on a wide range of scientific investigations, especially on magnetic reconnection and related particle acceleration, magnetized inertial confinement fusion (ICF) schemes, and laser interaction with high-density magnetized plasma.