Electron Density Oscillations in CC-RF Oxygen Plasma Investigated by Gaussian Beam Microwave Interferometry
Gaussian beam microwave interferometry (160 GHz, beam waist of 5 mm) is applied to study the electron density in capacitively coupled radio-frequency (RF) oxygen plasma. The microwave interferometry provides immediately the line-integrated electron density without model assumptions. In the considered range of RF power and total pressure, the investigations have shown that the oxygen plasma is dominated by electron density oscillations due to the attachment-induced ionization instability. The frequency of the mostly nonharmonic oscillations ranges between 0.3 and 3 kHz with peak-to-peak line-integrated electron density variations up to 3.5 × 1015 m-2.
Lighthouse Plasma Instability in a Capacitive RF Discharge
Instabilities in an asymmetric capacitively coupled radio frequency argon discharge occur within the pressure range of 70-100 Pa while adding low amounts of CF4. The development of these instabilities is highly dynamic in time and space. The instabilities strongly influence the optical plasma emission and electron density, respectively.
Reversible Chemisorption Gas-Gap Thermal Switch
Gas/sorbent combinations provide means to turn heat-conduction paths on and off. Single-stage gas-gap thermal switch based on reversible chemisorption of hydrogen gas by ZrNiH. Two-stage gas-gap thermal switch based on reversible desorption of O2 from MnO2 in first stage, followed by absorption in Cu on zeolite in second stage. Requires relatively low power. Used in sorption refrigeration systems designed to operate for long times without maintenance.