  Recently the drift-reduced Landau fluid six-field turbulence model within the
BOUT++ framework has been upgraded. In particular, this new model employs a new
normalization, adds a volumetric flux-driven source option, the Landau fluid
closure for parallel heat flux and a Laplacian inversion solver which is able
to capture n=0 axisymmetric mode evolution in realistic tokamak configurations.
These improvements substantially extended model's capability to study a wider
range of tokamak edge phenomena, and are essential to build a fully
self-consistent edge turbulence model capable of both transient (e.g., ELM,
disruption) and transport time-scale simulations.
