A low pressure discharge lamp, particularly a compact fluorescent lamp, having a plurality of constricting portions axially spaced apart and extending about the circular periphery of the envelope. The constricting portions, which include defined end segments projecting within the envelope, constrict the plasma discharge and spatially separate at least one of the discharge processes occurring within the plasma discharge and cause the separated process to take place in a different portion within the envelope so that the conditions for energy input and energy dissipation may be independently optimized.