ISTTOK, where the MCAD is placed between toroidal coils. Section 2 presents a short description of the HIBD and MCAD installation on ISTTOK. In Section 3 the.
28th EPS Conference on Contr. Fusion and Plasma Phys. Funchal, 18-22 June 2001
ECA Vol. 25A (2001) 1253-1256
INFLUENCE OF A NON-UNIFORM MAGNETIC FIELD ON THE MEASUREMENT OF THE ne×σ eff PROFILE BY HEAVY ION BEAM PROBING WITH A MULTIPLE CELL ARRAY DETECTOR I.S. Nedzelskiy, A. Malaquias, J.A.C. Cabral, C.A.F. Varandas Associação EURATOM/IST, Centro de Fusão Nuclear, Instituto Superior Técnico, 1049-001 Lisboa, Portugal 1. Introduction. The radial profile of the product ne×σeff (ne being the plasma density and σeff(Te) the effective cross section of the ionisation process) can be directly obtained using a heavy ion beam diagnostic (HIBD) and measuring the currents of secondary ions, is, created in collisions between the plasma electrons and the primary ions along their path inside the plasma, and collected by a multiple cell array detector (MCAD) [1]. For the double charged secondary ions the relation between is and ne×σeff is: is(r) = 2ip [ne×σeff ](r)λ(r)ξ(r)
(1)
where ip is the intensity of the primary beam, λ(r) is the primary trajectory length (sample length) from which the secondary ions are collected by the cell, and ξ(r) is the combined exponential beam attenuation coefficient [1]. In the range of 100 eV < Te
