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Numerical simulations to study turbulent magnetic field amplification by nonlinear interaction of high-power laser and kinetic Alfvén waves in laboratory and astrophysical plasmas
摘要： The model contouring the dynamics of transient nonlinear interaction between the high-frequency extraordinary-elliptically polarized laser (HFXPL) and low-frequency kinetic Alfvén wave (LFKAW) dynamics in the magnetized plasma is the focal point of the present investigation. The quasistatic ponderomotive force driven by the HFXPL pump induces density cavitation and humps in the low-frequency kinetic Alfvén wave. In order to study the intricate localized structures of HFXPL pump waves that evolve with time, the requisite dimensionless equations of the coupled system (HFXPL and LFKAW) are evaluated by using numerical methods in the nonlinear stage. The typical scale sizes of these structures in the early phase are ≈9 μm, and the typical time to grow is ≈10 ps. The ensemble-averaged magnetic power spectra are also presented, indicating energy cascade. The rendered investigations follow direct relevance to the experimental observations and are imperative in understanding turbulence in astrophysical scenarios.
关键词： kinetic Alfvén waves,high-power laser,astrophysical plasmas,laboratory plasmas,nonlinear interaction,turbulent magnetic field amplification
更新于2025-09-12 10:27:22
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AIP Conference Proceedings [AIP Publishing INTERNATIONAL CONFERENCE ON PHOTONICS, METAMATERIALS & PLASMONICS: PMP-2019 - Noida, India (14–16 February 2019)] INTERNATIONAL CONFERENCE ON PHOTONICS, METAMATERIALS & PLASMONICS: PMP-2019 - Stabilization of plane polarized Alfven waves by anomalous Doppler resonance
摘要： This work presents non-linear decay of plane polarized Alfven wave via anomalous Doppler resonance with an electron beam in a magnetized plasma. First order perturbation theory has been employed to derive the expressions for dispersion relation of Alfven waves and their growth rate. Numerical calculations have also been carried out for growth rate and unstable mode frequencies for typical plasma parameters. There exists two modes of wave propagation, one having frequency < ωci corresponds to Alfven wave, and the other has frequency approaching ωce which corresponds to electron cyclotron wave. The waves interact with the electron beam via normal and anomalous Doppler resonance. The normal resonance interaction increases the frequency of plane polarized Alfven wave but shows no growth or decay in amplitude. However, in anomalous resonance interaction the frequency remains unchanged and the wave stabilizes. The variation of frequency and growth rate with magnetic field and number density of plasma electrons is also discussed in the present paper. The phase velocity and the unstable frequency of the wave decrease with an increase in the number density of plasma electrons. The results of our work are applied to explain some of the experimental observations.
关键词： anomalous Doppler resonance,magnetized plasma,Alfven waves,growth rate,electron beam
更新于2025-09-11 14:15:04