Abstract Electromagnetic transverse perturbations propagating parallel to the external magnetic field in a
warm electron plasma, specifically the warm electron whistler waves, are simulated in κ distributed
electrons. The Vlasov-Maxwell phase-space continuum simulations are applied to the stable and
unstable (i.e., isotropic and anisotropic) VDFs including those with energetic tail, i.e., κ distribution.
The variation of real frequency from both numerical solution of dispersion relation and simulations
show limited sensitivity to electron temperature in low wave-number regime as compared to high
wave number regime, however the opposite holds for the imaginary frequency or the decay rate. For
large amplitude, nonlinear cases, simulated with anisotropic κ distributions the very low anisotropy
cases find the growth rate increasing with increasing the κ while this trend reverses for higher
anisotropy. The phase-space portraits of the these cases show that after the linear damping phase
of the evolution, the particles are trapped in the wave magnetic field leading to the wave amplitudes
oscillating about a mean value which follow the theoretical analysis [1].