Three-dimensional "particle in cell" simulations show that a quasistatic magnetic field can be generated in a plasma irradiated by a linearly polarized Laguerre-Gauss beam with a nonzero orbital angular momentum (OAM). Perturbative analysis of the electron dynamics in the low intensity limit and detailed numerical analysis predict a laser to electrons OAM transfer. Plasma electrons gain angular velocity thanks to the dephasing process induced by the combined action of the ponderomotive force and the laser induced-radial oscillation. Similar to the "direct laser acceleration," where Gaussian laser beams transmit part of its axial momentum to electrons, Laguerre-Gaussian beams transfer a part of their orbital angular momentum to electrons through the dephasing process.

Department of Physics Chalmers University of Technology SE 41296 Göteborg Sweden

ELI Beamlines Institute of Physics Czech Academy of Sciences 25241 Dolni Brezany Czech Republic

National Research Nuclear University MEPhI Moscow 115409 Russian Federation

P N Lebedev Physical Institute Moscow 119333 Russian Federation

Université de Bordeaux CNRS CEA UMR 5107 33405 Talence France

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Generation of intense magnetic wakes by relativistic laser pulses in plasma