Feature Request: Derive additional plasma parameters from known quantities

Plasma papers often describe the plasma in terms of a small number of dimensionless parameters. As a random example, a paper might report $k_B T_e / (m_e c^2) = 1/100$ and $\omega_{pe} / \Omega_{ce} = 1.0$. From that the plasma beta (as well as the ratio of Alfven speed to the speed of light) can be derived, but the value might not be explicitly stated in the paper. Being able to tell plasmapy a number of known facts and getting additional information on the plasma that can be uniquely determined would be very useful to compare across papers or set up the same situation in another code.
Since some of the papers concern PiC simulations, it would be useful if the mass ratio $m_i / m_e$ is not assumed by one of the user-determined parameters. Note that the mass ratio may be as small as 25, so things like electron inertia in the Alfven speed might be important.

No files, tests, or entry points are named. Start by defining the supported known quantities and the uniquely derivable outputs, including how an independently specified mass ratio affects the calculations. Done means an agreed API and implementation that derives the requested plasma parameters for the stated cases, with tests covering mass ratios as low as 25.