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3. Recent Progress on dispersion interferometers for nuclear fusion and low-temperature plasmas

Author

Akiyama, T., Van Zeeland, M.A., Carlstrom, T.N., Boivin, R.L., Brunner, K.J., Knauer, J., Yasuhara, R., Tanaka, K., Liu, H.Q., Zhou, Y., Oyama, Naoyuki, Sirinelli, A., Urabe, K., and Shirai, N.

Abstract

Dispersion interferometers (DI) measure a phase shift caused by difference of the phase velocities in a medium (dispersion) between the fundamental and the second harmonic of laser light, a straightforward application of which is the measurement of electron density in a plasma. Common to all implementations, the DI probe beam is a mixture of above two wavelengths, both of which are interfered at the shorter wavelength after traversing the diagnosed medium and a frequency doubling crystal. Unlike conventional interferometers, DIs are insensitive to path length changes by mechanical vibrations. This advantage arises because the two wavelengths propagate along the same path and, in the final doubling process, fully cancel the vibration induced phase shift. While vibration compensation can also be achieved with two separate lasers in a so-called “two-color vibration compensated” system, additional advantages of the DI include the lack of a reference leg, a single laser source with common noise between the two colors and intrinsic co-linearity of the two colors. Hence the DI is able to obtain high density resolution with simple hardware and small alignment effort. After application to Gas-Dynamic Trap (GDT), the density resolution of DIs has been improved further on various toroidal devices (TEXTOR, LHD, HL-2A, W7-X) in the last decade. This is mainly due to introductions of various phase modulation techniques and phase extraction methods. Extension of the bandwidth for electron-density-fluctuation measurements up to the MHz-range was demonstrated on DIII-D. Design and bench tests of DI systems have been implemented for EAST as well as future large devices including JT-60SA and ITER. This talk will review recent progress of the DI by above diagnostic techniques, as well as applications to low-temperature plasmas, where the DI also offers an excellent opportunity for low-noise electron-density measurements., Laser Aided Plasma Diagnostics 2019

Published
2020

4. First electron temperature and density measurements using the multi-pass Thomson scattering system with the laser amplification system in GAMMA 10/PDX

Author

Yoshikawa, M., primary, Mouri, T., additional, Nakanishi, H., additional, Kohagura, J., additional, Shima, Y., additional, Sakamoto, M., additional, Nakashima, Y., additional, Ezumi, N., additional, Minami, R., additional, Yamada, I., additional, Yasuhara, R., additional, Funaba, H., additional, Minami, T., additional, and Kenmochi, N., additional

Published
2020
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7. First electron temperature and density measurements of D-module plasma in GAMMA 10/PDX using Thomson scattering and microwave interferometer systems

Author

Yoshikawa, M., primary, Kohagura, J., additional, Shima, Y., additional, Nakanishi, H., additional, Mouri, T., additional, Suto, S., additional, Nojiri, K., additional, Terakado, A., additional, Ezumi, N., additional, Sakamoto, M., additional, Nakashima, Y., additional, Minami, R., additional, Yamada, I., additional, Yasuhara, R., additional, Funaba, H., additional, Minami, T., additional, Kenmochi, N., additional, Kuwahara, D., additional, and Meiden, H. Van der, additional

Published
2019
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10. Electron temperature measurements by the use of multi-pass Thomson scattering system in GAMMA 10/PDX

Author

Yoshikawa, M., primary, Ohta, K., additional, Wang, X., additional, Morishita, M., additional, Chikatsu, M., additional, Shima, Y., additional, Kohagura, J., additional, Yasuhara, R., additional, Sakamoto, M., additional, Nakashima, Y., additional, Imai, T., additional, Ichimura, M., additional, Yamada, I., additional, Funaba, H., additional, Kawataha, K., additional, and Minami, T., additional

Published
2015
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11. Electron temperature and density measurements by using the Thomson scattering system in the tandem mirror GAMMA 10

Author

Yoshikawa, M, primary, Nagasu, K, additional, Shimamura, Y, additional, Shima, Y, additional, Kohagura, J, additional, Kitagawa, K, additional, Morishita, M, additional, Sakamoto, M, additional, Nakashima, Y, additional, Imai, T, additional, Ichimura, M, additional, Kawarazaki, R, additional, Yamada, I, additional, Yasuhara, R, additional, Funaba, H, additional, and Minami, T, additional

Published
2013
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12. Current status of the LHD Thomson scattering system

Author

Yamada, I, primary, Narihara, K, additional, Funaba, H, additional, Yasuhara, R, additional, Kohmoto, T, additional, Hayashi, H, additional, Hatae, T, additional, Tojo, H, additional, Sakuma, T, additional, Yoshida, H, additional, Fujita, H, additional, and Nakatsuka, M, additional

Published
2012
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13. Radial electron temperature measurements by using newly installed Thomson scattering system in GAMMA 10

Author

Yoshikawa, M, primary, Yaguchi, F, additional, Miyata, Y, additional, Morimoto, M, additional, Shima, Y, additional, Nakashima, Y, additional, Ichimura, M, additional, Imai, T, additional, Yamada, I, additional, Kawahata, K, additional, Funaba, H, additional, Yasuhara, R, additional, Narihara, K, additional, Minami, T, additional, and Lee, J H, additional

Published
2012
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