Generalization of the theory of thermophoresis for a doublet of solid particles experiencing a temperature step on the surface

Using the linear operator approach, a theory of thermophoresis is constructed for the case of two homogenous solid spherical aerosol particles moving parallel to their center line. Formulas for the Stokes force, force of thermophoresis, and rate of thermophoresis of an aerosol particle with regard to a temperature step on its surface and the effect of the other particle are derived. Approximate engineering formulas are presented.