Plasma density fluctuations measurements by heavy ion beam probe with a multiple cell array detector on the tokamak ISTTOK

Abstract

It is recognized that the broad-band fluctuations observed in plasmas of thermonuclear devices are the cause of anomalously large energy and particle transport. Strong progress has been achieved on different plasma devices using a heavy ion beam probe (HIBP) diagnostic measuring the plasma potential and density fluctuations. Better understanding of turbulence properties can be obtained with a multiple cell array detector (MCAD) as plasma density fluctuations are measured simultaneously at a number of sample volumes. In this paper, the capabilities of the HIBP with MCAD for plasma density fluctuations measurements on the tokamak ISTTOK are analyzed (including restrictions due to sample volume size and path effects) and compared with preliminary experimental data. The upgrade of ISTTOK HIBP for better diagnostic performance is also discussed.