HELP: User subroutines for multi species system
 

Hi All,

I want to define the magnet force as a body force through a user-defined subroutine for a multi species system. The force is a function of the given magnetic intensity, and the concentration and molecular weight of each species. It actually is the sum of the force on each species.

So what are the macros for the concentration and molecular weight of species i? And what is the identifier of species i?

Thank you very much for your help!