I am a theoretical plasma physicist who just recently learned about this site. Having been a regular user of mathoverflow and mathstackexchange for the past year, I am very excited about the benefits this site could bring to my field. However, there is currently no Q&A category for plasma physics. How does one go about changing this? I should mention that there already are questions that should be categorized as plasma physics, e.g. here and here.
More generally, one could ask this same question but with "plasma physics" replaced by "biophysics" or any other major physics subfield that is not currently represented in the Q&A categories.
I understand that there are catch-all categories in place, such as "general physics." However, I feel that certain large subfields are just as "worthy" of having a dedicated Q&A category as are astronomy or high-energy theory.
I also understand that, so far, there are relatively few plasma physics questions. However, if this site is serious about being a tool for all branches of physics, then it ought to anticipate and encourage the substantial involvement of currently underrepresented, but large subfields.