An apparatus and method to concentrate a plasma from one or more plasma sources through at least one pathway. A first embodiment of the invention involves a method to concentrate a plasma for treating one or more articles with a selectively concentrated plasma generated from dissociating one or more gases, the method includes supplying one or more gases from a source to a first chamber; applying RF power to dissociate the one or more gases and create a plasma; withdrawing the dissociated one or more gases from the first chamber through at least one pathway; and supplying the dissociated one or more gases to a treatment chamber containing one or more articles, wherein the at least one pathway selectively concentrates the plasma in the at least one pathway by using a narrower pathway with a volume smaller than the treatment chamber to restrict the diffusion of the plasma to concentrate the plasma. A second embodiment of the invention involves an apparatus to concentrate a plasma to treat one or more articles.