Intermittent turbulence and coherent structure generation in a laboratory plasma

Strongly intermittent turbulence and the generation of coherent structures are observed in the shadow of a limiter in the Large Plasma Device (LAPD) at UCLA. The creation of both density enhancements (``blobs'') and density depletions (``holes'') is observed simultaneously, suggesting an interchange-like process. The blobs are observed to propagate out into the plasma edge while the holes propagate back into the core plasma. A statistical study of the coherent structures reveals a typical size of ten times the ion sound gyroradius and a typical velocity of one tenth the sound speed