TITLE
	Turbulence Imaging on the TORPEX Device
	
AUTHOR
	Stefan MUELLER

ABSTRACT 
	Regimes with a wide spectrum of electrostatic turbulent activity in the drift wave frequency 
	range are produced and characterized on the TORPEX experiment, a toroidal device in which 
	plasmas of Hydrogen and noble gases are produced by ECRH wave injection at 2.45GHz, with 
	powers up to 50kW, for durations up to 100ms. The dynamical behavior of macroscopic turbulent 
	structures is reconstructed by applying the conditional average sampling technique on a 
	shot-to-shot basis to movable electrostatic probes. The results for Argon plasmas typically 
	show the generation of large-scale structures and their motion in the direction of the ExB 
	drift. A new system of Langmuir probe arrays, dedicated to turbulence imaging, is being 
	installed on the TORPEX device. Covering up the whole poloidal cross-section with 92 tips 
	forming a hexagonal grid with a grid constant of 35 mm, the project represents the first 
	attempt of simultaneous imaging of the whole cross-section of a plasma column. The design 
	principles and the realization of this dedicated electrostatic imaging diagnostic will be 
	presented along with its first results and with possible alternative non-perturbative 
	optical imaging techniques.