1. Prospects for edge current density determination using LIBEAM on DIII-D
- Author
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K. H. Burrell, J. I. Robinson, R. T. Snider, D. K. Finkenthal, Daniel Thomas, R. J. Jayakumar, B. W. Rice, T. N. Carlstrom, M. A. Makowski, T.H. Osborne, A.S. Bozek, and D. G. Nilson
- Subjects
Physics ,Tokamak ,Zeeman effect ,DIII-D ,law.invention ,Computational physics ,symbols.namesake ,Stark effect ,law ,Electric field ,symbols ,Plasma diagnostics ,Pitch angle ,Magnetohydrodynamics ,Instrumentation - Abstract
The specific size and structure of the edge current profile has important effects on the magnetohydrodynamic stability and ultimate performance of many advanced tokamak (AT) operating modes. This is true for both bootstrap and externally driven currents that may be used to tailor the edge shear. Absent a direct local measurement of j(r), the best alternative is a determination of the poloidal field. Measurements of the precision (0.1°–0.01° in magnetic pitch angle and 1–10 ms) necessary to address issues of stability and control and provide constraints for EFIT are difficult to do in the region of interest (ρ=0.9–1.1). Using Zeeman polarization spectroscopy of the 2S–2P lithium resonance line emission from the DIII-D LIBEAM [D. M. Thomas, Rev. Sci. Instrum. 66, 806 (1995); D. M. Thomas, A. W. Hyatt, and M. P. Thomas, Rev. Sci. Instrum. 61, 340 (1990)] measurements of the various field components may be made to the necessary precision in exactly the region of interest to these studies. Because of the negli...
- Published
- 2001