Context: The location of coronal heating in magnetic loops has been the subject of a long-lasting controversy: does it occur mostly at the loop footpoints, at the top, is it random, or is the average profile uniform?
Aims: We try to address this question in model loops with MHD turbulence and a profile of density and/or magnetic field along the loop.
Methods: We use the Shell-Atm MHD turbulent heating model described in Buchlin & Velli (2007, ApJ, 662, 701), with a static mass density stratification obtained by the HydRad model (Bradshaw & Mason 2003, A&A, 401, 699). This assumes the absence of any flow or heat conduction subsequent to the dynamic heating.
Results: The average profile of heating is quasi-uniform, unless there is an expansion of the flux tube (non-uniform axial magnetic field) or the variation of the kinetic and magnetic diffusion coefficients with temperature is taken into account: in the first case the heating is enhanced at footpoints, whereas in the second case it is enhanced where the dominant diffusion coefficient is enhanced.
Conclusions: These simulations shed light on the consequences on heating profiles of the complex interactions between physical effects involved in a non-uniform turbulent coronal loop.