Fast magnetic field annihilation in the relativistic collisionless regime driven by two ultra-short high-intensity laser pulses

摘要

The magnetic quadrupole structure formation during the interaction of twoultra-short high power laser pulses with a collisionless plasma is demonstratedwith 2.5-dimensional particle-in-cell simulations. The subsequent expansion ofthe quadrupole is accompanied by magnetic field annihilation in theultrarelativistic regime, when the magnetic field can not be sustained by theplasma current. This results in a dominant contribution of the displacementcurrent exciting a strong large scale electric field. This field leads to theconversion of magnetic energy into kinetic energy of accelerated electronsinside the thin current sheet.