Naming conventions

[SolarDrew]

I think we've mostly been sticking to the same names for things like electron/ion density, but I think there are a few places where we may not have done. I can't remember if we have defined conventions written down anywhere for this sort of thing, but if we don't we probably should, and then we should add those conventions (or a link to them) to the contributor guide.

[lemmatum]

Perhaps a table of common plasma variables/properties in the docs? This would include the common name(s), the variable name we use, and a short description of what the property is/does.

[SolarDrew]

Yes, I like that idea.

[namurphy]

Yeah, I like all of these ideas! We should include the variable name we use in code and also the mathematical symbol that we use in equations in the documentation. We should also describe conventions for variable types in general, e.g., do we use f or 𝜈 for frequencies, 𝛺 or 𝜔 for angular frequencies, and so on with appropriate subscripts.

There are also multiple names for the same phenomena, like gyrofrequency vs. Larmor frequency. It would be confusing to use more than one name for things in the code base and documentation, but it would likely be helpful to list other names too in case someone does a search for them.

Cross-references: #176 and maybe #136, #273, #274, and #355.