Generation of megatesla magnetic fields by intense-laser-driven microtube implosions

Abstract

A microtube implosion driven by ultraintense laser pulses is used to produce ultrahigh magnetic fields. Due to the laser-produced hot electrons with energies of mega-electron volts, cold ions in the inner wall surface implode towards the central axis. By pre-seeding uniform magnetic fields on the kilotesla order, the Lorenz force induces the Larmor gyromotion of the imploding ions and electrons. Due to the resultant collective motion of relativistic charged particles around the central axis, strong spin current densities of $$\sim$$ ∼ peta-ampere/$$\hbox {cm}^{2}$$ cm 2 are produced with a few tens of nm size, generating megatesla-order magnetic fields. The underlying physics and important scaling are revealed by particle simulations and a simple analytical model. The concept holds promise to open new frontiers in many branches of fundamental physics and applications in terms of ultrahigh magnetic fields.

Magnetic field annihilation and charged particle acceleration in ultra-relativistic laser plasmas

“…The generation of magnetic field based on ultra intense laser-plasma interactions has been investigated intensively in recent years [104][105][106] . Furthermore, the interactions of beam-plasma are also discussed for strong magnetic dipoles generation [107,108] .…”

Laser scaling for generation of megatesla magnetic fields by microtube implosions

“…Recently, a novel concept called a microtube implosion (MTI) [25] has been proposed. MTI utilizes a structured target and intense laser pulses.…”

“…The kilotesla-order, uniform, pre-seeded magnetic fields [22,[26][27][28][29][30][31] parallel to the target central axis launch Larmor gyromotions of electrons and ions, deflecting their trajectories in the opposite direction. Near the target center, currents running on the envelope curves due to the deflected ions and electrons (referred to as Larmor holes [25]) form a strong spin current. Consequently, ultrahigh magnetic fields are generated in a collective manner, amplifying the original seed magnetic field by a factor of two to three orders of magnitude.…”

“…Previously, we proposed the principle of MTI and used two-dimensional (2D) particle-in-cell (PIC) simulations to demonstrate its characteristic behavior in terms of plasma parameters such as the plasma density, the current, and temperature of electrons [25]. In this work, we clarify the achievable maximum magnetic fields as a function of external parameters, including the applied laser intensity, laser energy, and target structure.…”

“…Previous studies have discussed a surprising phenomenon called polarity switching [25,37]. Polarity switching causes a plasma-current-driven magnetic field on the order of 0.1 -1 MT to initially grow on the central axis in the direction opposite to the seed magnetic field (antiparallel or reverse field regime) [25,37].…”