Types of Electric Discharge. Low-Temperature Plasma

The gas in the positive column of glow discharge, in arc discharge at high pressures and in certain other forms of discharge (as well as in the incandescent atmosphere of stars) is in the plasma state. The plasma represents a unique system of interacting particles and possesses specific properties. 

The plasma is also classified into high-temperature and low-temperature plasma. The low-temperature plasma specifying the state of gas in flames, in shock tubes and in electric discharge is of great kinetic interest. When the disturbance in the equilibrium distribution of energy caused by chemical processes is substantial, the plasma is non-isothermal. 

The conditions in a positive column of the usual type of glow discharge are a pressure of about 0.1 to 100 torr, a moderate gas temperature (a few hundred centigrades) and a high electronic temperature . These conditions resemble those for photochemical reactions where the role of fast electrons is played by photochemically active light quanta. With respect to their moderate energy fast electrons correspond rather to quanta of 

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