Plasma solenoid driven by a laser beam carrying an orbital angular momentum

Artikel i vetenskaplig tidskrift, 2018

A megagauss quasistatic axial magnetic field can be produced from the interaction of an intense laser beam carrying an orbital angular momentum with an underdense plasma. Three-dimensional 'particle in cell" simulations and analytical model demonstrate that orbital angular momentum is irreversibly transferred from a tightly focused radially polarized laser beam to electrons without any dissipative effect. A theoretical model describing the individual interaction of electrons with laser shows that particles gain angular momentum during their radial and longitudinal motion in the laser field. The electron rotation and the generated axial magnetic field survive to the end of the laser-plasma interaction and continue over a long time. The agreement between particle in cell simulations and the simplified model identifies routes to increase the intensity of the solenoidal magnetic field by controlling the laser beam characteristics, such as, for example, the orbital angular momentum and/or the pulse duration.