Dependence of vortex properties on height. (a) Area fraction (fill factor) covered by vortices; (b) horizontally averaged magnetic field strength in vortices (solid) and over the whole domain (dashed); (c) horizontally averaged unsigned vertical component of current in vortices (normalized to the density averaged over the whole domain); (d) horizontally averaged mass density in vortices (similarly normalized); (e) horizontally averaged temperature in vortices (solid curve) and over the entire domain (dashed curve); and (f) horizontally averaged total heating (viscous+resistive) in vortices (normalized to the total heating averaged over the whole domain). The region near the top boundary is shaded gray and may be affected by the imposed top boundary conditions and should be ignored.