Fuchs

Combined aerosol population dynamics: condensation growth (DiameterGrowthRate) and Brownian coagulation (BrownianCoagulationCoefficient + MonodisperseCoagulation), coupled so that the Fuchs-form coagulation coefficient K_12 drives the number-concentration ODE and the shared temperature T and particle density ρ_p parameterize both growth and coagulation. Implements Seinfeld & Pandis (2006) Ch. 13 Eqs. 13.11-13.13 (condensation), 13.47 and Table 13.1 (coagulation coefficient), and 13.65-13.67 (number-concentration dynamics). Migrated from Aerosol.jl src/dynamics.jl:279 (esm-540).

Brownian coagulation coefficient K_12 for two particles using the Fuchs interpolation formula (Seinfeld & Pandis 2006, Table 13.1). Valid across the continuum, transition, and free-molecular regimes. Computes Knudsen numbers, Cunningham slip corrections, Brownian diffusion coefficients, mean thermal velocities, particle mean free paths, and the Fuchs interpolation parameters g_1, g_2 as intermediate observed variables before assembling K_12. Migrated from Aerosol.jl src/dynamics.jl:75.