  Raytracing/Fokker-Planck (FP) simulations used to model lower-hybrid current
drive (LHCD) often fail to reproduce experimental results, particularly when
LHCD is weakly damped. A proposed reason for this discrepancy is the lack of
"full-wave" effects, such as diffraction and interference, in raytracing
simulations and the breakdown of raytracing approximation. Previous studies of
LHCD using non-Maxwellian full-wave/FP simulations have been performed, but
these simulations were not self-consistent and enforced power conservation
between the FP and full-wave code using a numerical rescaling factor. Here we
have created a fully-self consistent full-wave/FP model for LHCD that is
automatically power conserving. This was accomplished by coupling an overhauled
version of the non-Maxwellian TORLH full-wave solver and the CQL3D FP code
using the Integrated Plasma Simulator. We performed converged full-wave/FP
simulations of Alcator C-Mod discharges and compared them to raytracing. We
found that excellent agreement in the power deposition profiles from raytracing
and TORLH could be obtained, however, TORLH had somewhat lower current drive
efficiency and broader power deposition profiles in some cases. This
discrepancy appears to be a result of numerical limitations present in the
TORLH model and a small amount of diffractional broadening of the TORLH wave
spectrum. Our results suggest full-wave simulation of LHCD is likely not
necessary as diffraction and interference represented only a small correction
that could not account for the differences between simulations and experiment.
