Experimental investigation of double layers in expanding plasmas

Experimental investigation of double layers in expanding plasmas

Double layers DLs have been observed in a plasma reactor composed of a source chamber attached to a larger expanding chamber. Positive ion beams generated across the DL were characterized in the low plasma potential region using retarding field energy analyzers. In electropositive gases, DLs were formed at very low pressures between 0.1 and 1 mTorr with the plasma expansion forced by a strongly...

Waves in expanding electronegative plasmas containing double layers

Expanding electronegative EN plasmas have been previously observed, experimentally, to generate wave activity. Using a particle-in-cell PIC code we have investigated these waves in expanding EN plasmas containing a double layer DL between an upstream source region and an expanded downstream region. Oxygen reaction rates were used but modified to correspond more closely to experimental condition...

Ion acoustic waves and double-layers in electronegative expanding plasmas

Propagating double layers in electronegative plasmas

Double layers have been observed to propagate from the source region to the diffusion chamber of a helicon-type reactor filled up with a low-pressure mixture of Ar/SF6 N. Plihon et al., J. Appl. Phys. 98, 023306 2005 . In the present paper the most significant and new experimental results are reported. A fully self-consistent hybrid model in which the electron energy distribution function, the ...

Experimental Investigation of Electron-Acoustic Waves in Electron Plasmas

Electron-acoustic waves have strong linear Landau damping, but are observed as nonlinear BGK modes in experiments with pure electron plasmas. The waves have phase velocity vφ ≈ 1.3v̄, in agreement with theory, and the longest wavelength BGK states exhibit only relatively weak damping. Shorter wavelength modes exhibit a strong decay instability which can be experimentally controlled.