15th Topical Conference on High Temperature Plasma Diagnostics, 19 a 22 de Abril de 2004, San Diego, USA

	Possibilities of X-mode Correlation Reflectometry Measurements from the Upgraded KG8b Diagnostic on JET
	S. Hacquin, L. Meneses, I. Nunes, N. Cruz, L. Cupido, R. Prentice e os contributos do JET-EFDA
	Resumo
	The KG8b reflectometer on JET consists of 4 independent systems, each one probing the plasma with 2 different millimeter waves in the X-mode polarization, one at fixed frequency and the other one whose frequency can be swept step-by-step to allow correlation measurements. The technical characteristics and the actual status of the KG8b diagnostic are first presented. In particular we discuss the main constraints affecting the measurements - namely the attenuation in the wave-guides, the applied magnetic field value and the plasma scenario - thus highlighting the conditions in which measurements are possible. Some illustrative results show that useful information can be extracted when signals are reflected in the plasma edge region. A study of the effect of the ELM activity on the KG8b signals is then presented.