Theory of the negative differential conductivity of electrons due to electron-electron interaction in low-temperature plasma

The quantitative analysis of the mechanism of S- and N-type negative differential conductivity (NDC) of electrons in low-temperature plasma due to the electron-electron interaction (EEI) is presented. It is shown that EEI along with NDC of electrons can initiate the generation of high- frequency domains moving with velocities of the order drift velocity of electrons accompanied in some cases with the discontinuous constriction of positive columns of glow discharges. The estimations show that EEI can be displayed in a large number of gases and gas mixtures; comparisons with experiments and numerous simulations confirm the validity of the proposed theory. The use of powerful spectroscopic diagnostic methods is necessary for the tracing of dynamics excited species needed for elaboration of self-consistent description of NDC of electrons.