Speaker
Description
The transfer of angular momentum (AM) from circularly polarized or vortex laser beams to plasma offers a novel mechanism for controlling plasma morphology and self-generated fields. This work explores the collective plasma response initiated during tunnel-ionization, focusing on two ultrafast phenomena: spiral electron density modulation and axial magnetic field generation. Using an analytical model validated by 3D PIC simulations, we show that space-dependent electron drift motion induces transient spiral density structures. These evolve into spiral density waves and subsequent filaments via streaming instabilities. We identify these dynamics through Thomson scattering spectral signatures of the electron plasma waves. Additionally, the absorption of photon AM drives azimuthal currents, generating Tesla-level quasistatic magnetic fields. These results suggest that laser-driven AM transfer can substantially modify the plasma environment relevant to laser–plasma acceleration, where the resulting magnetic fields and density structures may influence beam transport, injection, and instability dynamics.
| Working group | WG1 |
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