121 / 2023-04-14 11:15:40

Generating axial magnetic fields via two plasmon decay driven by a twisted laser

magnetic field genration,Two plasmon decay,Laguerre-Gauss laser

惯性约束聚变物理学 > 黑腔和激光等离子体相互作用-II

We propose a new way of axial magnetic fields generation in a non-relativistic laser intensity regime by using a twisted light carrying orbital angular momentum (OAM) to stimulate two-plasmon decay (TPD) in a plasma. The growth of TPD driven by an OAM light in a Laguerre-Gauss (LG) mode is investigated through three dimensional fluid simulations and theory. TPD is intrinsically excited in a non-collimated way as the most unstable modes involve pairs of EPWs that propagate at fairly 2 large angles with respect to the propagation direction of the pump laser. This non-collimated geometry of the dominant modes is another key feature that would make TPD grow in a very distinguished way from the collimated forward/backward SRS and SBS in the previous OAM Stimulated Raman/ Brillouin Scatter (SRS/SBS) studies. A theory based on the assumption that the electron plasma waves (EPWs) are locally driven by a number of local plane-wave lasers predicts the maximum growth rate proportional to the peak amplitude of the pump laser field and is verified by the simulations. The OAM conservation during its transportation from the laser to the TPD daughter EPWs is shown by both the theory and the simulations. The theory predicts generation of ∼ 40T axial magnetic fields through the OAM absorption via TPD, which has perspective applications in the field of high energy density physics.