This is an example of the RDIs in magnetized gas. Specifically, the movie shows an xyz projection, with the initial magnetic field in the vertical direction (z), the acceleration of the grains in the x-z (width-height) direction, and the mutually perpendicular direction is depth (y). The colors show gas velocity, relative to mean, measured on slices on the xyz surfaces in the periodic box, while the black points show the dust in the same slice (the movie is in a frame moving with the mean dust velocity). Here the dust is charged and feels both magnetic/Lorentz and drag/Coulomb forces, and it is only drifting weakly (sub-sonically), in a medium with plasma beta of ~1. For more details, see Seligman et al. (in prep.)