Abstract: The kinetic Alfvén wave (KAW) eigenvector relations between the various physical fields (electric, magnetic, density, and velocity fields) are derived from a two-fluid model and are used to set up KAW modes in 2.5D particle-in-cell (PIC) simulations. The propagation of this wave is observed and its frequency is derived from its propagation speed. The frequency is also calculated by solving the dispersion relation derived from the two-fluid model, and also from a hot-plasma kinetic dispersion relation solver. Different plasma betas are simulated. We find that the frequency obtained from simulations matches closely with the kinetic dispersion relation, even though a two-fluid eigenvector is used to setup the wave. Two and more KAW wavenumber modes are introduced and their nonlinear interactions are studied. Energy decays more rapidly for the case with two or more input waves as compared to the single-wave case. It is found that the three-wave interactions transfer energy to other wavenumbers. At the same time there is also growth in magnetic energy at high parallel wavenumbers which are not directly linked by three-wave interactions. The energy is transferred to higher field-perpendicular wavenumbers via local interactions, while there appears very little energy transfer to higher field-parallel wavenumbers. Bispectral analysis also indicates that the three wave interactions strongly favor same parallel-wavenumber interactions. © 2023, Pleiades Publishing, Ltd.