  We investigate the dynamics of a closed corona cartesian reduced
magnetohydrodynamic (MHD) model where photospheric vortices twist the coronal
magnetic field lines. We consider two corotating or counter-rotating vortices
localized at the center of the photospheric plate, and additionally more
corotating vortices that fill the plate entirely. Our investigation is
specifically devoted to study the fully nonlinear stage, after the linear stage
during which the vortices create laminar and smoothly twisting flux tubes. Our
main goal is to understand the dynamics of photospheric vortices twisting the
field lines of a coronal magnetic field permeated by finite amplitude broadband
fluctuations. We find that depending on the arrangement and handedness of the
photospheric vortices an inverse cascade storing a significant amount of
magnetic energy may occur or not. In the first case a reservoir of magnetic
energy available to large events such as destabilization of a pre-CME
configuration develops, while in the second case the outcome is a turbulent
heated corona. Although our geometry is simplified our simulations are shown to
have relevant implications for coronal dynamics and CME initiation.
