  We use local numerical simulations to study a vertically stratified accretion
disk with a resistive mid-plane that damps magnetohydrodynamic (MHD)
turbulence. This is an idealized model for the dead zones that may be present
at some radii in protoplanetary and dwarf novae disks. We vary the relative
thickness of the dead and active zones to quantify how forced fluid motions in
the dead zone change. We find that the residual Reynolds stress near the
mid-plane decreases with increasing dead zone thickness, becoming negligible in
cases where the active to dead mass ratio is less than a few percent. This
implies that purely Ohmic dead zones would be vulnerable to episodic accretion
outbursts via the mechanism of Martin & Lubow (2011). We show that even thick
dead zones support a large amount of kinetic energy, but this energy is largely
in fluid motions that are inefficient at angular momentum transport. Confirming
results from Oishi & Mac Low (2009), the perturbed velocity field in the dead
zone is dominated by an oscillatory, vertically extended circulation pattern
with a low frequency compared to the orbital frequency. This disturbance has
the properties predicted for the lowest order r mode in a hydrodynamic disk. We
suggest that in a global disk similar excitations would lead to propagating
waves, whose properties would vary with the thickness of the dead zone and the
nature of the perturbations (isothermal or adiabatic). Flows with similar
amplitudes would buckle settled particle layers and could reduce the efficiency
of pebble accretion.
