The shape of the liquid cone is determined by the electrohydrodynamic equations governing the liquid flow. The pressure difference across the liquid surface is given as the difference between the surface tension and the Maxwell stress. This relation, together with the Bernoulli and mass-conservation equations yields the equation for the shape of the cone. The equation contains the electric field intensity at the liquid surface, which is calculated by solving an appropriate Poisson equation. The Poisson equation solution needs the surface to be given, so we use an iterative procedure in which we improve the assumed shape at each step, to satisfy the shape equation in the weighted residual sense.
Results are as follows.
The cone angle is close to the Taylor cone angle only for large needle radii. For smaller needle radii the cone angle is current dependent, the angle decreasing with increasing current. The protrusion length is also current dependent, but values are generally much smaller than those calculated by Kingham and Swanson. Further Comments on Field Adsorption R.G. Forbes Surface Sci. This note deals with issues raised as a consequence of the author's paper on field adsorption at the 1989 International Field Emission Symposium.