Cross-beam energy transfer in a magnetized high energy density plasma

Cross-beam energy transfer (CBET) is a laser-plasma interaction where power is transferred between two intersecting lasers in a plasma environment. The amount of power transfer between the beams is determined by the plasma response to the ponderomotive force at the difference in frequency, Δω, and wavevector, Δk, between the two lasers. We have derived the CBET transfer between lasers in a magnetized plasma using Vlasov-Maxwell theory with a background magnetic field and have modeled magnetized CBET using PIC simulations. Several findings include the ability of cross-polarized lasers to transfer power (which cannot occur in the unmagnetized case), the reduction of the transfer rate between parallel-polarized lasers and only in the kinetic model we find significant power transfer over a broad range of (Δω, Δk) due to nonlinear ion cyclotron Landau damping. We will discuss the similarities and differences between the kinetic and PIC results. CBET plays an important role in direct and indirect ignition designs, and we will discuss potential impacts of these results to inertial confinement fusion ignition designs relevant to cases with self-generated or externally applied magnetic fields.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and by the LLNL-LDRD program under Project Number 23-ERD-025.