Coherent Magnetic Field Fluctuation Measurements

72164S03-I Plasma instabilities are a key factor limiting the performance of fusion devices, and the identification and understanding of these instabilities will be required before fusion can be an economically attractive energy source. To help in the identification and characterization of the instabilities, this project will develop technology for high-frequency, high-spatial-resolution measurements of magnetic field fluctuations. The technology will modify the motional Stark-effect diagnostic, using improvements in the frequency response and increased sensitivity to achieve the desired measurements. Phase I will develop detailed plans for the design and specifications of a high frequency polarimeter. Estimates of typical instability structures and magnetic field amplitudes will be made and compared to the expected sensitivity of the diagnostic. A proof-of-principal experiment will be designed for later implementation in Phase II. Commercial Applications and Other Benefits as described by awardee: Detailed magnetic field measurements of plasma instabilities should provide real-time feedback for improving the performance and economical attractiveness of fusion energy as a viable energy source.