Schematic view of the setup of the full-kinetic 3D-3V simulations presented in this study. Left panel: Density, magnetic field, and current profiles at t = 0 along the direction of the inhomogeneity (x-axis) in the “strong gradient” simulation. Right panel: 3D visualization of the ion density in the “strong gradient” simulation at , the LHDI fluctuations are highlighted in the unstable plane (yellow) and in a cut that is perpendicular to the ambient magnetic field.