Interference of parallel cylindrical Langmuir probes

Current to a cylindrical probe of arbitrary cross section is discussed. Pre vious results for circular cylinders at the high bias and moderate radius R of interest for electrodynamic bare tethers, for which space charge may be ignored over a large neighborhood of the probe, depend in separate ways on both R and perimeter p. These results are extended to a general convex cro ss section by introducing certain equivalent radius R-eq. For any concave c ross section, results use a proper equivalent perimeter p(eq), in addition to R-eq. Finally, for the joint cross section of separate parallel probes, certain effective perimeter p(eff) replaces p(eq). Rules to determine R-eq, p(eq), and p(eff) are used to discuss collection interference among two or more parallel cylinders when brought from far away to contact. (C) 2001 Am erican Institute of Physics.