A fast scanning Langmuir probe system for ASDEX-Upgrade divertor

A fast scanning Langmuir probe system (LPS) for ASDEX-Upgrade's divertor pl asma investigations was designed, manufactured and operated. Profiles of io n saturation current density, J(sat) electron temperature, T-ed, electron d ensity, N-ed, floating potential, V-fl, and Mach number have been recorded for ohmic (OH) and low/medium power neutral beam heated (NI) discharges. In these cases the probe can access both divertor legs, allowing comparison o f plasma parameters in the two diverters and investigations of the private flu?; region. Strong divertor asymmetries, complex plasma flow patterns and changes in the power flow to the divertor targets, depending on ion gradB drift direction, density and divertor geometry, have been observed. (C) 199 9 Elsevier Science B.V. All rights reserved.