Effect of Grid Geometry on IEC Performance

Abstract

Grid geometry plays an important role in the performance of a gridded spherical IEC device because the ion recirculation, and hence the reaction rate, is strongly affected by the orientation and size of openings in the cathode in grid design. In Chap. 3 we learned that cathodes with reasonably large openings face each other so that an ion could easily recirculate via ion microchannels (corresponding to a high effective transparency) and perform much better than either a solid cathode or a cathode with holes that do not point directly at each other (i.e., causing a low effective transparency). Aside from these major features, various researchers have investigated the effect of a variety of grid opening geometries [1]. However, these experiments have been generally inconclusive, because they operated in the grid performance “saturation” regime, wherein the maximum symmetry is already achieved and any further increase in symmetry through addition of more wires does not cause significant improvement in the observed reaction rate.