Characteristics of the radiation of copper atoms and ions in a discharge from a hot hollow cathode

Abstract

Noting one pecu l i a r i t y of the f i l l ing of exci ted a tomic leve l s as a r e s u l t of r e c o m b i n a t i o n p r o c e s s e s , i . e . , that it o c c u r s " f r o m the top down, " we can pose the ques t ion of whether r ecombina t i on p r o c e s s e s can be used for selective filling of certain excited atomic levels. Since filling "from the top down" in a real nonequilibrium plasma of moderate density occurs simultaneously with ordinary filling "from the bottom up" produced by collisions with electrons, it is obvious that the latter type of filling must be impeded. This can readily be done in a decaying plasma. In an ordinary steady-state plasma, this requires maintenance of a high degree of ionization and advantageous recombination conditions: a large number of slow ions and electrons. These conditions obviously cannot be provided solely by varying the discharge regime, since the requirements to be, met are incompatible.