Triggering of Buneman instability and existence of multiple double layers in laboratory plasma.

We report experimentally observed triggering criteria for Buneman instability and boundary conditions for existence of multiple double layers (MADL) in glow discharge plasma. The MADLs are generated by accelerating plasma electrons towards a positively biased electrode submerged in it. The boundary conditions for the formation and existence of MADL are obtained from the experiment in terms of electron drift velocity ( ν d ) and electron thermal velocity ( ν t e ). The MADL is found to exist within the range 3 ν t e ≥ ν d ≥ 1.3 ν t e . For the condition ν d ≥ 1.3 ν t e , rise of an instability and simultaneous formation of MADL is observed in the experiment. The analysis of fluctuations in floating potential showed that the instability has all the characteristics of Buneman instability. [ABSTRACT FROM AUTHOR]