Thermodynamic-Equilibrium

Conserved total concentration of a single inorganic aerosol species (e.g. NH, Na, Ca, K, Mg, Cl, NO3, SO4) in the ISORROPIA v1 thermodynamic equilibrium model. The total concentration `total` is held constant over time (D(total)/dt = 0), representing the user-supplied input constraint: the total moles per unit air volume of that ionic group across all phases (gas + aqueous + solid). This component is instantiated once per tracked ion group inside the top-level Isorropia system. Migrated from Aerosol.jl src/isorropia/isorropia.jl `Species`.