Feature wish list

[bendudson]

Core physics

• Zhdanov closure: need this to ensure our equations are properly valid for multiple species. We currently have something Braginskii-like which is only valid in the trace approximation.
• 9-point stencils: Need 9 point stencil operators to allow support for non-orthogonal grids that accurately resolve the target wall. The most important of these is the one used for perpendicular neutral diffusion.
  See issue Implement proper handling of non-orthogonal grids #66 and PR WIP: Operators for non-orthogonal meshes #88
• 2D velocity fluid neutral model: Full momentum equation for neutrals in cartesian directions. This would likely much improve our fluid neutral model transport, and may have an additional benefit for molecules. See PR WIP: Neutral full velocity model #105
• 1D reservoir model: To bring 1D closer to 2D by mimicking cross-field neutral transport. See PR Add simple 1D reservoir model #204
• Molecular reactions: These are very important for detachment. Not started yet.
• Support for more impurities: Need to implement Argon, Nitrogen and Carbon ADAS reactions.

Development

• Balance tests: We need to have CI tests that check for energy and particle balance in a 2D case.

Input/Output

• Flow diagnostics: It would be really useful to have all of the flow operators output diagnostics so that we can post-process fluxes. Some of these are already done.
• LaTeX output: It would be good to have a way to check which equations the code was solving. One way would be to output LaTeX equations.
  The terms included may depend on the quantities available in the state, so this should be taken into account. This would help catch errors caused by putting components in the wrong order.

[mikekryjak]

Updated with some more wishlist items in preparation for the workshop @bendudson