Influence of nitrogen impurities on an electron-excited helium atoms   concentration in the self-sustained normal dc glow discharge at atmospheric   pressure
  The influence of nitrogen impurities on the parameters of the self-sustained normal dc glow discharge at atmospheric pressure was studied. The concentrations of the low-excited helium atoms in states 2_1s, 2_1p, 2_3s and 2_3p were determined in the atmospheric pressure glow discharge in helium (99.98%He) and in helium with a nitrogen admixture. It was shown that the adding of nitrogen into helium (less 5%) leads to the increase of both interelectrode gap voltage and gas temperature. At the same time the drastically reduction of concentration of the low-excited helium atoms in cathode region even at nitrogen admixture of 0.5 % is occurred. 
Valery Arkhipenko (LGDP), Andrey Kirillov (LGDP), Leanid Simonchik   (LGDP), Siargey Zgirouski (LGDP)