Time-Domain Benchmark Solutions for Bernstein Waves

Abstract

In previous work, we introduced a semi-analytical method for computing time-domain solutions of linearized Vlasov problems. Rather than representing the plasma response as a sum of residues associated with Landau poles, the method constructs a regularized frequency-domain response spectrum that is subsequently inverted numerically. Explicit applications have so far been limited to unmagnetized plasmas. In this work, we extend the construction to plasmas with a uniform background magnetic field and a Maxwellian equilibrium distribution. We apply the resulting formulation to the electrostatic ion-Bernstein density response of a plasma with kinetic ions and adiabatic electrons, and provide error estimates for truncating both the spectral integration domain and the cyclotron-harmonic expansion. The solution serves as a time-domain reference for damped finite-$k_\parallel$ regimes, in which dispersion-relation roots alone are insufficient for pointwise-in-time verification of simulation codes. Finally, we indicate how the framework can be extended to fully electromagnetic problems.