Track Effects in Positronium Formation

International audienceWe discuss some aspects important for interpretation of the Ps formation process in liquids and molecular media: (1) inhomogeneity of intratrack reactions and parameters of the e+ track, (2) final states of e+, its solvation in polar and nonpolar liquids, relation to e+ mobility, (3) quasi-neutrality of the e+ blob and its ambipolar outdiffusion, (4) appearance of the “in-blob” and “out-of-the-blob” positron fractions, and (5) electric field effect on Ps formation