Can simplified models accurately represent complex plasma behavior? This study assesses the validity of using the incompressibility hypothesis to describe compressible plasma dynamics, focusing on the Kelvin-Helmholtz Instability (KHI). Through comparisons between the compressible Euler equations (GAMERA code) and the incompressible Navier-Stokes equations (STRATOSPEC code), the research investigates single-mode and multi-mode initial perturbations with and without a parallel magnetic field. By decreasing the Mach number in GAMERA and viscosity/diffusion in STRATOSPEC, the inviscid incompressible regime is reached. The study analyzes density fields, 1D profiles, and spectral densities to compare results. The findings demonstrate satisfactory agreement between the two codes, particularly in vortex dynamics and the damping of small-scale structures, validating the incompressibility hypothesis under specific conditions.
Published in Frontiers in Physics, this research aligns with the journal's focus on cutting-edge research across the entire field of physics. The study's investigation of the Kelvin-Helmholtz Instability, a fundamental phenomenon in plasma physics, falls squarely within the journal's scope. By exploring the limits of the incompressibility hypothesis, the research contributes to a deeper understanding of plasma dynamics and its applications in astrophysics and fusion energy.