Electrostatic turbulence in the edge of TPE-RX and driving mechanisms

In order to understand the driving mechanisms that underlie the turbulence in the plasma edge of fusion devices, contemporary measurements of light emission fluctuations with the gas puff imaging diagnostic and of the electrostatic potential with Langmuir probes are carried out in the TPE-RX plasma device. The analysis made with the conditional average technique demonstrates a clear link between the two types of structures, with a phase shift of pi/2. This relation suggests that the curvature driven modes are a possible source of free energy for edge turbulence in this machine, as similarly found in other plasma devices.