Microwave Imaging Reflectometer for TEXTOR
Authors: T. Munsat, E. Mazzucato, H. Park, B.H. Deng, C.W. Domier, N.C. Luhmann, Jr., J. Wang, Z.G. Xia, A.J.H. Donné, and M. van de Pol
Date of PPPL Report: July 2002
Presented at: the 14th Topical Conference on High Temperature Plasma Diagnostics, July 8-11, 2002, in Madison, Wisconsin. Proceedings to be published in Review of Scientific Instruments.
Understanding the behavior of fluctuations in magnetically confined plasmas is essential to the advancement of turbulence-based transport physics. Though microwave reflectometry has proven to be an extremely useful and sensitive tool for measuring small density fluctuations in some circumstances, this technique has been shown to have limited viability for large amplitude, high kq fluctuations and/or core measurements. To this end, a new instrument based on 2-D imaging reflectometry has been developed to measure density fluctuations over an extended plasma region in the TEXTOR tokamak. This technique is made possible by collecting an extended spectrum of reflected waves with large-aperture imaging optics. Details of the imaging reflectometry concept, as well as technical details of the TEXTOR instrument will be presented. Data from roof-of-principle experiments on TEXTOR using a prototype system is presented, as well as results from a systematic off-line study of the advantages and limitations of the imaging reflectometer.