  In this paper, we present an interior penalty discontinuous Galerkin finite
element scheme for solving diffusion problems with strong anisotropy arising in
magnetized plasmas for fusion applications. We demonstrate the accuracy
produced by the high-order scheme and develop an efficient preconditioning
technique to solve the corresponding linear system, which is robust to the mesh
size and anisotropy of the problem. Several numerical tests are provided to
validate the accuracy and efficiency of the proposed algorithm.
