This parameter, which defaults to zero, corresponds to an axisymmetric extra torque added everywhere to the disk material so as to induce a global radial drift of the latter, in addition to the viscous drift. This was implemented for the “in the place migration” technique developed by Masset & Papaloizou (2003), section 5.6 (see in particular Eq. 34). The value of ImposedDiskDrift corresponds to the radial velocity imposed at (this radial velocity depends on radius so that the drift is steady state, {i.e.} so that is independent of , where is the radial drift velocity induced by this extra torque).