The volume flow per unit time per unit field strength through the whole plug.
See also: electro-osmosis
Source:
PAC, 1972, 31, 577. 'Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry' on page 620 (https://doi.org/10.1351/pac197231040577)