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20 results on '"Yasuhara R"'

1. Initial operation and data processing on a system for real-time evaluation of Thomson scattering signals on the Large Helical Device

Author

Hammond, K. C., primary, Laggner, F. M., additional, Diallo, A., additional, Doskoczynski, S., additional, Freeman, C., additional, Funaba, H., additional, Gates, D. A., additional, Rozenblat, R., additional, Tchilinguirian, G., additional, Xing, Z., additional, Yamada, I., additional, Yasuhara, R., additional, Zimmer, G., additional, and Kolemen, E., additional

Published
2021
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2. Improvement in multipass Thomson scattering system comprising laser amplification system developed 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
2021
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4. Analysis method for Thomson scattering diagnostics in GAMMA 10/PDX

Author

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

Published
2016
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5. Validations of calibration-free measurements of electron temperature using double-pass Thomson scattering diagnostics from theoretical and experimental aspects

Author

Tojo, H., primary, Yamada, I., additional, Yasuhara, R., additional, Ejiri, A., additional, Hiratsuka, J., additional, Togashi, H., additional, Yatsuka, E., additional, Hatae, T., additional, Funaba, H., additional, Hayashi, H., additional, Takase, Y., additional, and Itami, K., additional

Published
2016
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6. Calibrations of the LHD Thomson scattering system

Author

Yamada, I., primary, Funaba, H., additional, Yasuhara, R., additional, Hayashi, H., additional, Kenmochi, N., additional, Minami, T., additional, Yoshikawa, M., additional, Ohta, K., additional, Lee, J. H., additional, and Lee, S. H., additional

Published
2016
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7. Reconstruction of high temporal resolution Thomson scattering data during a modulated electron cyclotron resonance heating using conditional averaging

Author

Kobayashi, T., primary, Ida, K., additional, Itoh, K., additional, Yoshinuma, M., additional, Moon, C., additional, Inagaki, S., additional, Yamada, I., additional, Funaba, H., additional, Yasuhara, R., additional, Tsuchiya, H., additional, Ohdachi, S., additional, Yoshimura, Y., additional, Igami, H., additional, Shimozuma, T., additional, Kubo, S., additional, and Tsujimura, T. I., additional

Published
2016
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9. Edge profile measurements using Thomson scattering on the KSTAR tokamak

Author

Lee, J. H., primary, Oh, S., additional, Lee, W. R., additional, Ko, W. H., additional, Kim, K. P., additional, Lee, K. D., additional, Jeon, Y. M., additional, Yoon, S. W., additional, Cho, K. W., additional, Narihara, K., additional, Yamada, I., additional, Yasuhara, R., additional, Hatae, T., additional, Yatsuka, E., additional, Ono, T., additional, and Hong, J. H., additional

Published
2014
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13. First results of electron temperature measurements by the use of multi-pass Thomson scattering system in GAMMA 10

Author

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

Published
2014
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16. Design of the polarization multi-pass Thomson scattering system

Author

Yasuhara, R., primary, Yoshikawa, M., additional, Morimoto, M., additional, Yamada, I., additional, Kawahata, K., additional, Funaba, H., additional, Shima, Y., additional, Kohagura, J., additional, Sakamoto, M., additional, Nakashima, Y., additional, Imai, T., additional, and Minami, T., additional

Published
2012
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17. Increased signal separation upgrade permits preliminary electron anisotropy measurements with Heliotron J multi-pass Thomson diagnostic.

Author

Qiu D, Minami T, Kado S, Inagaki S, Wang C, Matsutani R, Toba S, Luo M, Zhang P, Kenmochi N, Ohshima S, Kobayashi S, Okada H, Mizuuchi T, Konoshima S, Yasuhara R, and Nagasaki K

Abstract

A signal separation system is constructed on the multi-pass Thomson scattering system of Heliotron J to solve the problem of overlapping scattered light signals for the electron temperature anisotropy measurement. The phenomenon of overlapping scattered light signals is relieved by operating the signal separation system. A Raman scattering experiment is undertaken to verify the separation effect of the signal separation system. Two scattered light signals corresponding to two adjacent incidences of one laser shot were extended to 104 ns. Moreover, we applied the multi-pass Thomson scattering system with signal separation system to the electron temperature anisotropy measurement. No anisotropy was observed within the error bars in the initial experiment.

Published
2023
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18. Design of a dual scattering angle multi-pass Thomson scattering system with signal separation function on Heliotron J.

Author

Qiu D, Minami T, Kado S, Matsutani R, Toba Y, Kenmochi N, Takahashi C, Wang C, Luo M, Zhang P, Ohshima S, Kobayashi S, Okada H, Mizuuchi T, Konoshima S, Yasuhara R, Inagaki S, and Nagasaki K

Abstract

This paper proposes a design of dual scattering angles multi-path Thomson scattering system with a signal separation function to solve the overlapping phenomenon of scattered light signals and to increase the measurement accuracy for the investigation of anisotropic electron velocity distribution. Furthermore, an optical path design is proposed to demonstrate how overlapping scattered light signals can be separated by setting the optical path in a limited room with a compact layout, which makes the incident interval between two overlapping scattered light signals 1.7 times longer than that of our current system. The specific position of each optical component existing in the system is determined via a Gaussian beam analysis to avoid damage caused by overexpansion of spot size with the application of two cooperating image relay systems. Conversely, a polychromator is optimized by resetting the pass waveband of the interference filter combination to achieve high accuracy in electron temperature (T e ) measurement corresponding to two scattering angles simultaneously.

Published
2023
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19. Development of a high-speed full digital processing phase detector for interferometry.

Author

Minami T, Ohtani Y, Ohshima S, Nagasaki K, Ito Y, Nakanishi H, Yasuhara R, Funaba H, Yamada I, and Akiyama T

Abstract

This study describes the development of a fully digital-type phase detector for plasma interferometry. This detector functions even in situations in which the phase changes rapidly or the input signal is too small to derive the correct phase shift from the intermediate frequency (IF) signal. The detector directly converts the IF signal waveform of the interferometer to the phase shift signal by means of data processing in a logic circuit. Thus, the phase is derived from the whole waveform of the IF signal. The IF signal of the interferometer is converted to in-phase and quadrature-phase signals by Hilbert transformation, processed by a digital low-pass filter, and converted to polar coordinates by a coordinate rotation digital computer algorithm to obtain the phase shift. A simulation of the high-speed full digital processing phase detector shows that a fringe jump does not occur unless the phase change rate exceeds 0.8 × 10 6 rad/s. This value is sufficiently large compared to the phase change velocity in rapid density increase resulting from a pellet injection. The phase conversion is simulated using a real IF signal from an interferometer measured with a Heliotron J device. The results show that the phase signal is correctly calculated by the full digital processing method from the IF signal, the phase derivation of which is typically difficult to obtain when using a conventional analog phase detector.

Published
2018
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20. High time resolved electron temperature measurements by using the multi-pass Thomson scattering system in GAMMA 10/PDX.

Author

Yoshikawa M, Yasuhara R, Ohta K, Chikatsu M, Shima Y, Kohagura J, Sakamoto M, Nakashima Y, Imai T, Ichimura M, Yamada I, Funaba H, and Minami T

Abstract

High time resolved electron temperature measurements are useful for fluctuation study. A multi-pass Thomson scattering (MPTS) system is proposed for the improvement of both increasing the TS signal intensity and time resolution. The MPTS system in GAMMA 10/PDX has been constructed for enhancing the Thomson scattered signals for the improvement of measurement accuracy. The MPTS system has a polarization-based configuration with an image relaying system. We optimized the image relaying optics for improving the multi-pass laser confinement and obtaining the stable MPTS signals over ten passing TS signals. The integrated MPTS signals increased about five times larger than that in the single pass system. Finally, time dependent electron temperatures were obtained in MHz sampling.

Published
2016
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