Streamer Formation in Plasma with a Temperature Gradient

Turbulence produced by a temperature gradient in a collisional plasma is investigated. The system evolves to a state in which highly elongated streams of plasma move up and down the temperature gradient. The resulting transport greatly exceeds estimates based on mixing-length arguments. It is argued that such streams are the preferred nonlinear state of turbulent fluctuations driven by both $\nabla T_e$ and $\nabla T_i$.