Electron concentration reduction in a combustion product plasma due to the formation of negative ions

The paper is concerned with the role of negative ions in a combustion product plasma, which is important from the standpoint of the possible reduction of electron concentration and, consequently, of plasma conductivity in the low temperature region. In an attempt to gain a better understanding of this problem, electron concentrations were determined experimentally in combustion products containing potassium in the temperature range 2000-2300 K; simultaneous measurements were made of the concentration of free potassium atoms and temperature. It is shown that the observed reduction in electron concentration is due primarily to the presence of NCO3(-) ions in the plasma.