This paper concerns electroconvectional stability of a conduction stat
e in an electrolyte layer flanked by cation-permselective walls (elect
rodialysis membranes, electrodes) under potentiostatic conditions. It
is shown through a numerical finite difference solution of the linear
stability problem that above a certain voltage threshold the basic con
duction state becomes electroconvectionally unstable. Marginal stabili
ty curves in the voltage/wave number plane are calculated and the depe
ndence of the critical threshold characteristics on the system's param
eters (ionic diffusivities ratio, electroconventional Peclet number) s
tudied. Electroconvectional instability is shown to occur for an arbit
rary ionic diffusivities ratio. A model problem of electroconvection i
n a loop under potentiostatic conditions is solved explicitly for a st
eady state. It is shown that above a certain voltage threshold; the qu
iescent conduction in the loop bifurcates into a pair of electroconvec
tional steady state circulations. (C) 1996 American Institute of Physi
cs.