Current density measurements for electrons emitted by electrodes of a low pressure RF capacitive discharge

摘要

The report is dedicated to a spectral method of current density measurements for electrons emitted by bare or insulated electrodes of an RF capacitive low pressure discharge (RFCD) in helium. In a DC glow discharge (DCGD) it was possible to carry out such measurements not only using the proposed new method but by purely electrical one for comparison. The numerical results of both experimental sets turned out to be of the same order of magnitude. Literature information on initial electron velocities was used to determine electron density n_(e0) for RFCD with bare and insulated electrodes and for DCGD. The dependence of n_(e0) on voltage and driving frequency was investigated for the RF discharge. The analysis of the obtained experimental data showed that at the same physical conditions avalanche ionization intensities within the electrode sheaths of both RFCD and DCGD did not differ much for these two kinds of glow discharge.