Electron avalanches and diffused γ-mode in radio-frequency capacitively coupled atmospheric-pressure microplasmas D.W. Liu Felipe Iza Michael G. Kong 2134/5213 https://repository.lboro.ac.uk/articles/journal_contribution/Electron_avalanches_and_diffused_-mode_in_radio-frequency_capacitively_coupled_atmospheric-pressure_microplasmas/9576470 Space-, time- and wavelength-resolved optical emission profiles suggest that the helium emission at 706 nm can be used to indicate the presence of high energy electrons and estimate the sheath in helium rf discharges containing small concentration of air impurities. Furthermore, the experimental data supports the theoretical predictions of energetic electron avalanches transiting across the discharge gap in rf microdischarges and the absence of an α-mode. Nonetheless, microdischarges sustained between bare metal electrodes and operating in the γ-mode can produce diffuse glowlike discharges rather than the typical radially constricted plasmas observed in millimeter-size rf atmospheric-pressure γ discharges. 2009-08-25 15:34:32 Electron avalanches Glow discharges Helium High-frequency discharges Plasma diagnostics Plasma impurities Plasma sheaths Mechanical Engineering not elsewhere classified