Calculation of collisionless space-charge sheaths method of matched asymptotic expansions vs. patching

Summary form only given, as follows. In this work, a comparison is performed of results predicted by the method of matched asymptotic expansions and by different variants of patching in three problems of the theory of space-charge sheaths: a collisionless steady-state sheath, a matrix sheath, and a collisionless RF sheath. In each problem, results are compared between themselves and with the exact solution. In all the cases, patching provides results which are accurate to the first approximation in the sheath voltage but not to the second one, irrespective of details of patching.