  The most promising technique for the control of neoclassical tearing modes in
tokamak experiments is the compensation of the missing bootstrap current with
electron-cyclotron current drive. In this frame, the dynamics of magnetic
islands has been studied extensively in terms of the modified Rutherford
equation, including the presence of current drive, either analytically
described or computed by numerical methods. In this article, a self-consistent
model for the dynamic evolution of the magnetic island and the driven current
is derived, which takes into account the island's magnetic topology and its
effect on the current drive. The model combines the modified Rutherford
equation with a ray-tracing approach to electron-cyclotron wave propagation and
absorption. Numerical results exhibit a decrease in the time required for
complete stabilization with respect to the conventional computation (not taking
into account the island geometry), which increases with increasing initial
island size and radial misalignment of the deposition.
