Simulation of phase space hole growth and the development of intermittent plasma turbulence

Abstract

An unstable, highly intermittent state of turbulence is observed to evolve from a quiescent homogeneous plasma that is linearly stable. This intermittent state, which consists of isolated phase space density holes, produces a pronounced non-Gaussian distribution of fluctuation amplitudes. The skewness becomes increasingly more negative with time. The plasma is nonlinearly unstable because the holes grow in amplitude by accelerating to regions of higher average phase space density. The instability can be interpreted as a collection of colliding, growing holes and, in its early stages, is consistent with theoretical predictions for the clump instability. A series of runs with a single isolated hole indicates that an isolated hole grows for any finite electron-ion drift velocity. The isolated hole growth rate is consistent with theoretical predictions. The implications of the instability to laboratory and space plasma are discussed. © 1985 American Institute of Physics.