Employing nematic liquid crystals in a homeotropic cell with a photosensitive wall. dissipative vortex pairs are selectively induced by external illumination and the interaction law is characterized for pairs of opposite topological charges. Contrary to the phenomenological fit with a force inversely proportional to the distance. the data provide evidence that nonlinear mobility effec... https://www.parisnaturalfoodes.shop/product-category/anise/