  The Landau collision integral is an accurate model for the small-angle
dominated Coulomb collisions in fusion plasmas. We investigate a high order
accurate, fully conservative, finite element discretization of the nonlinear
multi-species Landau integral with adaptive mesh refinement using the PETSc
library (www.mcs.anl.gov/petsc). We develop algorithms and techniques to
efficiently utilize emerging architectures with an approach that minimizes
memory usage and movement and is suitable for vector processing. The Landau
collision integral is vectorized with Intel AVX-512 intrinsics and the solver
sustains as much as 22% of the theoretical peak flop rate of the Second
Generation Intel Xeon Phi, Knights Landing, processor.
