Proton radiography of magnetic field produced by ultra-intense laser irradiating capacity-coil target

TL;DR

This study demonstrates the generation and measurement of a 40T magnetic field produced by ultra-intense laser irradiation of a capacity-coil target, revealing its temporal evolution and high energy conversion efficiency.

Contribution

It introduces a novel method to produce and characterize ultra-strong magnetic fields using ultra-short laser pulses on capacity-coil targets.

Findings

Magnetic flux density of 40T measured.

Magnetic field lasts over 100 picoseconds.

Laser to magnetic field energy conversion efficiency up to 20%.

Abstract

Ultra-intense ultra-short laser is firstly used to irradiate the capacity-coil target to generate magnetic field. The spatial structure and temporal evolution of huge magnetic fields were studied with time-gated proton radiography method. A magnetic flux density of 40T was measured by comparing the proton deflection and particle track simulations. Although the laser pulse duration is only 30fs, the generated magnetic field can last for over 100 picoseconds. The energy conversion efficiency from laser to magnetic field can reach as high as ~20%. The results indicate that tens of tesla (T) magnetic field could be produced in many ultra intense laser facilities around the world, and higher magnetic field could be produced by picosecond lasers.