Coordinate, speed, acceleration, and forces acting in the x-direction on a fluid parcel in the convection zone as a function of time. Panels a, b, and c show the coordinate, speed, and acceleration. The thin vertical lines indicate the times where a different cork is used to trace the pathline. Panels d–h show the various forces in the simulation (blue) in comparison to the total acceleration (red). Panels g and h together make up the artificial diffusion term B_diff in Eq. (4).