[Abridged] Aims. We provide an important step toward a better understanding
of the magnetorotational instability (MRI)-dust coevolution in protoplanetary
disks by presenting a proof of concept that dust evolution ultimately plays a
crucial role in the MRI activity. Methods. First, we study how a fixed
power-law dust size distribution with varying parameters impacts the MRI
activity, especially the steady-state MRI-driven accretion, by employing and
improving our previous 1+1D MRI-driven turbulence model. Second, we relax the
steady-state accretion assumption in this disk accretion model, and partially
couple it to a dust evolution model in order to investigate how the evolution
of dust (dynamics and grain growth processes combined) and MRI-driven accretion
are intertwined on million-year timescales. Results. Dust coagulation and
settling lead to a higher gas ionization degree in the protoplanetary disk,
resulting in stronger MRI-driven turbulence as well as a more compact dead
zone. On the other hand, fragmentation has an opposite effect because it
replenishes the disk in small dust particles. Since the dust content of the
disk decreases over million years of evolution due to radial drift, the
MRI-driven turbulence overall becomes stronger and the dead zone more compact
until the disk dust-gas mixture eventually behaves as a grain-free plasma.
Furthermore, our results show that dust evolution alone does not lead to a
complete reactivation of the dead zone. Conclusions. The MRI activity evolution
(hence the temporal evolution of the MRI-induced α-parameter) is
controlled by dust evolution and occurs on a timescale of local dust growth, as
long as there is enough dust particles in the disk to dominate the
recombination process for the ionization chemistry. Once it is no longer the
case, it is expected to be controlled by gas evolution and occurs on a viscous
evolution timescale.Comment: 23 pages, 13 figures, Accepted for publication in A&