This man's number is twice the magnetic energy density times the square of a typical length scale, all over the dynamic viscosity times the magnetic diffusivity. That dimensionless quantity named for 
This man's number is twice the magnetic energy density times the square of a typical length scale, all over the dynamic viscosity times the magnetic diffusivity. That dimensionless quantity named for this man appears in an equation modifying the critical Rayleigh number for convective instability in the presence of a uniform magnetic field. This man and Velikhov originated the study of the magnetorotational instability, and he derived an analytic approximation for the effects of dynamical friction, or gravitational drag. He introduced a tensor form of the virial theorem that includes his namesake potential energy tensor. He also considered relativistic effects on the stability of an n = 3 polytrope, deriving a critical value of approximately 5.83 over the square of the mean mass per electron in solar mass units. For 10 points, name this man who thus derived the upper mass limit for a white dwarf.
This man's number is twice the magnetic energy density times the square of a typical length scale, all over the dynamic viscosity times the magnetic diffusivity.
Subrahmanyan Chandrasekhar