Radial profile measurements of plasma pressure-like fluctuations with the heavy ion beam diagnostic on the tokamak ISTTOK

R B Henriques; A Malaquias; I S Nedzelskiy; C Silva; R Coelho; H Figueiredo; H Fernandes

doi:10.1063/1.4891045

Radial profile measurements of plasma pressure-like fluctuations with the heavy ion beam diagnostic on the tokamak ISTTOK

Rev Sci Instrum. 2014 Nov;85(11):11D848. doi: 10.1063/1.4891045.

Authors

R B Henriques¹, A Malaquias¹, I S Nedzelskiy¹, C Silva¹, R Coelho¹, H Figueiredo¹, H Fernandes¹

Affiliation

¹ Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.

PMID: 25430261
DOI: 10.1063/1.4891045

Abstract

The Heavy Ion Beam Diagnostic (HIBD) on the tokamak ISTTOK (Instituto Superior Técnico TOKamak) has been modified, in terms of signal conditioning, to measure the local fluctuations of the neσ1,2(Te) product (plasma density times the effective ionization cross-section) along the tokamak minor diameter, in 12 sample volumes in the range of -0.7a < r < 0.7a, with a maximum delay time of 1 μs. The corresponding signals show high correlation with the magnetic Mirnov coils in the characteristic MHD frequency range of ISTTOK plasmas and enable the identification of tearing modes. This paper describes the HIBD signal conditioning system and presents a preliminary analysis of the radial profile measurements of local neσ1,2(Te) fluctuations.