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2. Study of the pellet ablation cloud using the tomography technique for two-directional simultaneous photography in GAMMA 10/PDX.

Author

Yoshikawa, M., Nakashima, Y., Kohagura, J., Shima, Y., Kobayashi, S., Minami, R., Ezumi, N., and Sakamoto, M.

Subjects
PLASMA density, TOMOGRAPHY, PRODUCTION planning, PLASMA production, PHOTOGRAPHY
Abstract

The pellet ablation mechanism is an interesting subject for plasma fuelling in fusion plasmas. In GAMMA 10/PDX, pellet injection experiments for higher density plasma production are planned to conduct detached plasma experiments in the higher density plasma condition. We measured the pellet ablation cloud by using the two-directional simultaneous photography system in GAMMA 10/PDX. The tomography reconstruction technique was used for considering the pellet trajectory in the plasma and pellet ablation. The three-dimensional pellet trajectory and pellet ablation images in the plasma were clearly obtained for the first time, to the best of our knowledge. [ABSTRACT FROM AUTHOR]

Published
2024
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4. Progress of divertor simulation research toward the realization of detached plasma using a large tandem mirror device

Author

Nakashima, Y., Takeda, H., Ichimura, K., Hosoi, K., Oki, K., Sakamoto, M., Hirata, M., Ichimura, M., Ikezoe, R., Imai, T., Iwamoto, M., Hosoda, Y., Katanuma, I., Kariya, T., Kigure, S., Kohagura, J., Minami, R., Numakura, T., Takahashi, S., Yoshikawa, M., Asakura, N., Fukumoto, M., Hatayama, A., Hirooka, Y., Kado, S., Kubo, H., Masuzaki, S., Matsuura, H., Nagata, S., Nishino, N., Ohno, N., Sagara, A., Shikama, T., Shoji, M., Tonegawa, A., and Ueda, Y.

Published
2015
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8. Recent results of divertor simulation research using an end-cell of a large tandem mirror device

Author

Nakashima, Y., Takeda, H., Ichimura, K., Hosoi, K., Sakamoto, M., Hirata, M., Ichimura, M., Ikezoe, R., Imai, T., Ishii, T., Kariya, T., Katanuma, I., Kohagura, J., Minami, R., Numakura, T., Ueda, H., Yoshikawa, M., Asakura, N., Furuta, T., Hatayama, A., Hirooka, Y., Kado, S., Masuzaki, S., Matsuura, H., Nagata, S., Nishino, N., Ohno, N., Sagara, A., Shikama, T., Shoji, M., Toma, M., Tonegawa, A., and Ueda, Y.

Published
2013
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9. Effects from the Target Plate Geometry on Fluctuations of Helium Plasma in the Linear Divertor Simulator Magnum-PSI

Author

Yoshikawa, M., Tanaka, H., Hayashi, Y., Kajita, S., van der Meiden, H.J., Vernimmen, J.W.M., Morgan, T.W., Kohagura, J., Shima, Y., Togo, S., Ezumi, N., Nakashima, Y., Sakamoto, M., and Science and Technology of Nuclear Fusion

Subjects
Magnum-psi, Fluctuation, Condensed Matter Physics, Divertor simulator
Abstract

With the help of the linear divertor simulation device Magnum-PSI, a fluctuation investigation of the impact of the target plate geometry was conducted. We simultaneously quantify coherent low-frequency fluctuations with a newly built 70-GHz microwave reflectometry system, a reciprocating probe, a light emission detector system, and a fast-framing camera system. The strong low-frequency fluctuations were observed at both the electron density and the plasma radiations by moving the target plate along the magnetic field line. Furthermore, a strong peak in fluctuation intensity and the influence of the target plate tilt angle on the fluctuation intensity were noted.

Published
2022

10. Publisher’s Note: “Study of detached plasma profile in the divertor simulation experimental module of tandem mirror GAMMA 10/PDX” [AIP Advances 11, 125231 (2021)]

Author

Yoshikawa, M., primary, Kohagura, J., additional, Ezumi, N., additional, Iijima, T., additional, Nojiri, K., additional, Terakado, A., additional, Nakashima, Y., additional, Kariya, T., additional, Numakura, T., additional, Hirata, M., additional, Minami, R., additional, Sakamoto, M., additional, Ichimura, M., additional, Islam, M. S., additional, Shima, Y., additional, Yasuhara, R., additional, Yamada, I., additional, Funaba, H., additional, Minami, T., additional, Kenmochi, N., additional, Kuwahara, D., additional, and van der Meiden, H. J., additional

Published
2022
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11. Study of detached plasma profile in the divertor simulation experimental module of tandem mirror GAMMA 10/PDX

Author

Yoshikawa, M., Kohagura, J., Ezumi, N., Takaaki, Iijima, Kunpei, Nojiri, Akihiro, Terakado, Nakashima, Y., Kariya, T., Numakura, T., and Hirata, M.

Subjects
Physics::Plasma Physics, Physics::Space Physics
Abstract

A divertor simulation experimental module (D-module) in the tandem mirror GAMMA 10/PDX was used for the study of plasma detachment. In previous studies, it was difficult to measure far-upstream plasma parameters in the D-module, and only electrostatic probes on the target plate were used to perform electron temperature and density measurements. To study the detached plasma structure, a Thomson scattering (TS) system and a microwave interferometer system have been installed to measure the inside plasma parameters of the D-module, and a movable electrostatic probe has been placed at the inlet of the D-module to measure the inlet plasma density and temperature. The TS system in the central cell observed the electron temperature and density of the core plasma simultaneously. These measurements revealed the entire density and temperature structure from the core plasma to the divertor plate. The line average electron density measured by the microwave interferometer showed a rollover behavior during detachment. The results indicated that the ionization region was located around the center of the D-module, and it appears to move upstream along the axis.

Published
2021

12. Impact of additional plasma heating on detached plasma formation in divertor simulation experiments using the GAMMA 10/PDX tandem mirror

Author

Nakashima, Y., Islam, M.S., Iijima, T., Sakamoto, M., Ezumi, N., M.Yoshikawa, Asakura, Nobuyuki, Fukumoto, Masakatsu, Hatayama, A., Hirata, M., Ichimura, M., Ikezoe, R., Imai, T., Islam, M.M., Kariya, T., Kohagura, J., Masuzaki, S., Minami, R., Nakano, T., Nojiri, K., Numakura, T., Sawada, K., Shoji, M., Terakado, A., Togo, S., Yamashita, S., Yoshimoto, T., Nobuyuki, Asakura, and Masakatsu, Fukumoto

Subjects
Physics::Plasma Physics, Mathematics::General Topology
Abstract

The transition of a detached to attached plasma experiment has been performed in GAMMA 10/PDX by applying an additional plasma heating pulse of electron cyclotron heating (ECH). In a plasma detachment experiment, a short pulse (25 ms) of ECH was applied at the east plug-cell to examine the effects of electron heating on the plasma parameters in the D-module. It was found that the ion flux increased significantly during ECH injection. In the ECH injection period, the ion flux increased with the increasing impurity injection, which indicates the impurity ion components are enhanced by ionization in the D-module due to the application of ECH. During ECH injection period, the increase of the ion flux near the corner of the target plate shows a clear dependence on the gas species. The 2D visible emission has been captured by the high-speed camera and a bright emission near the corner of the target has been observed. The spectroscopic measurement in the D-module shows that the impurity ion emission increases remarkably during ECH injection. These results indicate the detached plasma change to the attached state.

Published
2019

13. Measurement of axial phase difference of density fluctuations owing to spontaneously excited waves by using microwave reflectometer on GAMMA 10/PDX

Author

Sekine, R., primary, Hirata, M., additional, Ikezoe, R., additional, Jang, S., additional, Kubota, Y., additional, Kayano, H., additional, Sugata, K., additional, Aizawa, T., additional, Noguchi, D., additional, Kim, D., additional, Sugimoto, Y., additional, Matsuura, R., additional, Yamazaki, H., additional, Ichimura, M., additional, Yoshikawa, M., additional, Kohagura, J., additional, Nakashima, Y., additional, Ezumi, N., additional, and Sakamoto, M., additional

Published
2021
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14. 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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15. Erratum: “Blob- and hole-like structures outstanding during the transition from attached to detached divertor states in GAMMA 10/PDX” [Phys. Plasmas 25, 082505 (2018)]

Author

Tanaka, H., primary, Sakamoto, M., additional, Ezumi, N., additional, Nojiri, K., additional, Terakado, A., additional, Mikami, T., additional, Kinoshita, Y., additional, Kobayashi, K., additional, Yoshikawa, M., additional, Kohagura, J., additional, and Ohno, N., additional

Published
2021
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20. Recent development in GAMMA 10 experiment

Author

Yatsu, K., Cho, T., Higaki, H., Hirata, M., Hojo, H., Ichimura, M., Ishii, K., Ishimoto, Y., Itakura, A., Katanuma, I., Kohagura, J., Minami, R., Nakashima, Y., Numakura, T., Saito, T., Saosaki, S., Takemura, Y., Tatematsu, Y., Yoshida, M., and Yoshikawa, M.

Published
2002
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22. 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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24. A theory on the sensitivity of a silicon surface-barrier detector including a thermal charge-diffusion effect

Author

Cho, T., Hirata, M., Takahashi, E., Teraji, T., Yamaguchi, N., Matsuda, K., Takeuchi, A., Kohagura, J., Ogura, K., Kondoh, T., Osawa, A., Yatsu, K., Tamano, T., and Miyoshi, S.

Subjects
Crystal detectors -- Research, Silicon -- Research, X-rays -- Research, Physics
Abstract

A theoretical model of the x-ray responses of silicon surface-barrier (SSB) detectors was developed under a configuration of a widely used detector structure for plasma x-ray diagnostics. The model consisted of a signal contribution from thermally diffusing charge created in the field-free substrate region within a diffusion length from the depletion layer. This was accompanied signal contributions coming from charge created in the depletion layer. The model was found to predict a large signal contribution from the charge-diffusion effect on the SSB responses to high-energy x-rays.

Published
1992

28. List of participants

Author

Abe, M., primary, Abo, M., additional, Abukawa, T., additional, Adachi, J., additional, Agui, A., additional, Aita, O., additional, Aiura, Y., additional, Ajello, J., additional, Akaki, O., additional, Akazawa, H., additional, Aksela, H., additional, Aksela, S., additional, Allen, J., additional, Altun, Z., additional, Amemiya, K., additional, Amusia, M., additional, An, K., additional, Andersen, J., additional, Aoki, S., additional, Arakawa, I., additional, Araki, T., additional, Arp, U., additional, Asensio, M., additional, Awaya, Y., additional, Awazu, K., additional, Azuma, H., additional, Azuma, Y., additional, Baba, Y., additional, Bando, H., additional, Bao, Z., additional, Becker, U., additional, Bengtsson, P., additional, Bobashev, S., additional, Bocquet, A., additional, Breton, J., additional, Cai, Y., additional, Caldwell, C., additional, Cauletti, C., additional, Chainani, A., additional, Che, J., additional, Chen, C., additional, Chen, L., additional, Chen, X., additional, Cherepkov, N., additional, Cho, T., additional, Christou, C., additional, Chung, J., additional, Couprie, M., additional, Cramer, S., additional, Da Silva, L., additional, Daimon, H., additional, Deguchi, K., additional, Dessau, D., additional, Dhanak, V., additional, Dolmatov, V., additional, Drube, W., additional, Echigo, S., additional, Ehresmann, A., additional, Eisebitt, S., additional, Ejima, T., additional, Ejiri, A., additional, Endo, O., additional, England, J., additional, Enta, Y., additional, Fadley, C., additional, Feldhaus, J., additional, Filatova, E., additional, Finazzi, M., additional, Finkenthal, M., additional, Fischer, D., additional, Flechsig, U., additional, Franzén, K., additional, Frasinski, L., additional, Fujikawa, T., additional, Fujimori, A., additional, Fujimori, S., additional, Fujisawa, M., additional, Fujita, K., additional, Fujita, M., additional, Fukui, K., additional, Fukutani, H., additional, Ghijsen, J., additional, Gluskin, E., additional, Guo, Q., additional, Guyon, P., additional, Hague, C., additional, Hall, R., additional, Hamamatsu, H., additional, Han, Z., additional, Hansen, J., additional, Hanyu, T., additional, Happo, N., additional, Hara, T., additional, Harada, I., additional, Harada, Y., additional, Hasegawa, M., additional, Hasegawa, S., additional, Hatano, T., additional, Hatherly, P., additional, Hattori, T., additional, Hayaishi, T., additional, Hayasi, T., additional, Heck, C., additional, Heinzmann, U., additional, Hieda, K., additional, Higashiyama, K., additional, Hirai, Y., additional, Hiraya, A., additional, Hirayama, T., additional, Hirose, S., additional, Hishikawa, A., additional, Hopkirk, A., additional, Horikawa, Y., additional, Hosaka, N., additional, Huber, K., additional, Huff, W., additional, Hussain, Z., additional, Hwang, C., additional, Ibrahim, K., additional, Ibuki, T., additional, Ichikawa, K., additional, Ichikawa, M., additional, Igarashi, J., additional, Iguchi, Y., additional, Iimura, K., additional, Iinuma, D., additional, Iketaki, Y., additional, Ikeura, H., additional, Imada, S., additional, Imaizumi, Y., additional, Imanishi, A., additional, Inokuchi, H., additional, Inoue, I., additional, Ishigame, M., additional, Ishiguro, E., additional, Ishii, H., additional, Ishii, T., additional, Ishijima, H., additional, Ishizue, I., additional, Isoyama, G., additional, Ito, K., additional, Itoh, M., additional, Itoh, Y., additional, Iwami, M., additional, Iwano, K., additional, Iwasaki, K., additional, Iwata, S., additional, Jacobsen, C., additional, Jikimoto, T., additional, Jo, T., additional, Johansson, L., additional, Johansson, U., additional, Jouda, K., additional, Jung, C., additional, Kabachnik, N., additional, Kaindl, G., additional, Kakizaki, A., additional, Kamada, M., additional, Kamata, A., additional, Kamenskikh, I., additional, Kameta, K., additional, Kamiya, K., additional, Kamiya, Y., additional, Kan'no, K., additional, Kanomata, T., additional, Kasaya, M., additional, Kashiwakura, T., additional, Kato, R., additional, Kato, Y., additional, Katoh, R., additional, Kaurila, T., additional, Kawai, J., additional, Kawamura, T., additional, Kayanuma, Y., additional, Kaznacheyev, K., additional, Kennedy, E., additional, Kiguchi, M., additional, Kihara, H., additional, Kimpara, Y., additional, Kimura, A., additional, Kimura, H., additional, Kimura, K., additional, Kimura, S., additional, Kinoshita, T., additional, Kirm, M., additional, Kisker, E., additional, Kitade, T., additional, Kitajima, M., additional, Kitajima, Y., additional, Kitamura, H., additional, Kitaura, M., additional, Kobayashi, K., additional, Kobayashi, M., additional, Koda, T., additional, Kohagura, J., additional, Koide, T., additional, Koike, F., additional, Koike, M., additional, Koike, T., additional, Koizumi, T., additional, Kojima, T., additional, Kondo, K., additional, Kondo, Y., additional, Kono, M., additional, Kono, S., additional, Korde, R., additional, Koseki, T., additional, Kosugi, N., additional, Kotani, A., additional, Kotani, M., additional, Kouchi, N., additional, Kowalski, M., additional, Koyama, M., additional, Koyano, I., additional, Krause, M., additional, Krupa, J., additional, Kumigashira, H., additional, Kuninobu, T., additional, Kurita, S., additional, Kusaka, M., additional, Kutluk, G., additional, Lablanquie, P., additional, Lama, F., additional, Larkins, F., additional, Latimer, C., additional, Lebrun, T., additional, Lee, D., additional, Lee, K., additional, Lee, T., additional, Legrand, F., additional, Lewis, B., additional, Li, D., additional, Lindau, I., additional, Liu, F., additional, Lodha, G., additional, Lu, E., additional, Lushchik, A., additional, Lyakhovskaya, I., additional, Mårtensson, N., additional, Ma, Y., additional, Machida, S., additional, Maeda, F., additional, Maeyama, S., additional, Maezawa, H., additional, Manakov, N., additional, Margaritondo, G., additional, Masui, S., additional, Masuoka, T., additional, Matsui, F., additional, Matsukawa, T., additional, Matsumoto, M., additional, Matsumoto, S., additional, Matsushita, T., additional, Matsuzawa, M., additional, Mattogno, G., additional, Messina, A., additional, Mikhailin, V., additional, Mimura, K., additional, Minami, T., additional, Misu, A., additional, Mitsuishi, T., additional, Mitsuke, K., additional, Mitsumoto, R., additional, Miyahara, T., additional, Miyamae, T., additional, Miyamoto, N., additional, Miyauchi, H., additional, Mizokawa, T., additional, Morgan, H., additional, Mori, I., additional, Mori, T., additional, Morin, P., additional, Morioka, Y., additional, Mosnier, J., additional, Munro, I., additional, Murakami, E., additional, Murata, T., additional, Murata, Y., additional, Muro, T., additional, Nagakura, I., additional, Nagaoka, S., additional, Nagata, T., additional, Nahon, L., additional, Nakagawa, K., additional, Nakai, I., additional, Nakai, S., additional, Nakai, Y., additional, Nakaishi, H., additional, Nakajima, N., additional, Nakamura, H., additional, Nakamura, M., additional, Nakatake, M., additional, Nakazawa, M., additional, Namatame, H., additional, Namioka, T., additional, Nanba, T., additional, Naoe, S., additional, Nasu, K., additional, Neeb, M., additional, Nenner, I., additional, Nishihara, Y., additional, Nishioka, H., additional, Niwano, M., additional, Nordgren, J., additional, Norman, D., additional, Nowak, C., additional, Nyholm, R., additional, Nylén, H., additional, Ogasawara, H., additional, Ogata, T., additional, Oh, S., additional, Ohara, J., additional, Ohashi, H., additional, Ohchi, T., additional, Ohmori, K., additional, Ohnishi, A., additional, Ohno, N., additional, Ohta, T., additional, Oji, H., additional, Okada, K., additional, Okajima, T., additional, Okane, T., additional, Okuda, T., additional, Okunishi, M., additional, Okusawa, M., additional, Olson, C., additional, Onellion, M., additional, Ono, I., additional, Ono, K., additional, Onsgaard, J., additional, Onuki, H., additional, Oshima, M., additional, Ouchi, I., additional, Ouchi, Y., additional, Oura, M., additional, Park, C., additional, Park, S., additional, Perera, R., additional, Petroff, Y., additional, Poliakoff, E., additional, Pong, W., additional, Prabhakaran, K., additional, Pratt, R., additional, Qvarford, M., additional, Rader, O., additional, Rahn, S., additional, Randall, K., additional, Reininger, R., additional, Rosenberg, R., additional, Rubensson, J., additional, Sainctavit, P., additional, Saito, N., additional, Saito, T., additional, Saitoh, T., additional, Saitoh, Y., additional, Sakamoto, K., additional, Sakano, M., additional, Sakisaka, Y., additional, Samson, J., additional, Sarma, D., additional, Sasaki, T., additional, Sasano, T., additional, Sato, H., additional, Sato, N., additional, Sato, S., additional, Sato, Y., additional, Savchenko, E., additional, Schattke, W., additional, Schlachter, F., additional, Schmidt, V., additional, Schwentner, N., additional, Seki, K., additional, Sekiguchi, T., additional, Sekitani, T., additional, Sekiyama, A., additional, Seno, H., additional, Shafi, M., additional, Sham, T., additional, Sheng, L., additional, Shi, C., additional, Shidara, T., additional, Shigemasa, E., additional, Shimada, H., additional, Shimada, K., additional, Shimamura, I., additional, Shimizu, Y., additional, Shimoyama, I., additional, Shin, S., additional, Shiraga, H., additional, Shirai, M., additional, Shishidou, T., additional, Shmaenok, L., additional, Shobatake, K., additional, Simon, M., additional, Smith, N., additional, Soda, K., additional, Solov'yov, A., additional, Sonntag, B., additional, Spanke, D., additional, Stankevitch, V., additional, Steinberger, I., additional, Steiner, P., additional, Suga, S., additional, Sugawara, H., additional, Sutherland, D., additional, Suzuki, I., additional, Suzuki, M., additional, Suzuki, N., additional, Suzuki, S., additional, Suzuki, T., additional, Taguchi, Y., additional, Takahashi, N., additional, Takahashi, T., additional, Takakuwa, Y., additional, Takata, Y., additional, Takatsuchi, K., additional, Takeichi, A., additional, Takenaka, H., additional, Takizawa, Y., additional, Tanaka, A., additional, Tanaka, K., additional, Tanaka, M., additional, Tanaka, S., additional, Tanaka, T., additional, Tang, J., additional, Tani, K., additional, Taniguchi, M., additional, Tayu, T., additional, Terada, S., additional, Terminello, L., additional, Tezuka, H., additional, Tezuka, Y., additional, Thissen, R., additional, Tinone, M., additional, Tokue, I., additional, Tonner, B., additional, Toyota, E., additional, Troussel, P., additional, Ueda, K., additional, Ueda, Y., additional, Ueno, N., additional, Uhrberg, R., additional, Ukai, M., additional, Umehara, T., additional, Uozumi, T., additional, Urisu, T., additional, Vaeterlein, P., additional, Van der Laan, G., additional, Van Hove, M., additional, Viane, P., additional, Voss, J., additional, Wang, X., additional, Watanabe, M., additional, Watanabe, N., additional, Watanabe, Y., additional, Weaver, J., additional, West, J., additional, van Wezenbeek, E., additional, Whitfield, S., additional, Woodruff, D., additional, Wu, L., additional, Wu, R., additional, Xu, P., additional, Xu, W., additional, Yagi, K., additional, Yagi, S., additional, Yagishita, A., additional, Yamada, T., additional, Yamakawa, T., additional, Yamamoto, H., additional, Yamamoto, M., additional, Yamamoto, Y., additional, Yamanaka, T., additional, Yamanouchi, K., additional, Yamashita, K., additional, Yanagihara, M., additional, Yang, S., additional, Yang, Y., additional, Yeom, H., additional, Yimagawa, M., additional, Ynzunza, R., additional, Yokoya, T., additional, Yokoyama, T., additional, Yoshida, A., additional, Yoshida, H., additional, Yoshi, K., additional, Yoshimura, D., additional, Yuri, M., additional, Zama, T., additional, Zeitoun, P., additional, Zhang, X., additional, Zhang, Y., additional, Zimmerer, G., additional, and Zimmermann, R., additional

Published
1996
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29. Impact of additional plasma heating on detached plasma formation in divertor simulation experiments using the GAMMA 10/PDX tandem mirror

Author

Nakashima, Y., Islam, M.S., Iijima, T., Yokodo, T., Sakamoto, M., Ezumi, N., Yoshikawa, M., Asakura, Nobuyuki, Fukumoto, Masakatsu, Hatayama, A., Hirata, M., Ichimura, K., Ichimur, M., Ikezoe, R., Imai, T., Islam, M.M., Kariya, T., Katanuma, I., Kohagura, J., Lee, G., Masuzaki, S., Minami, R., Nakano, Tomohide, Nojiri, K., Numakura, T., Sawada, K., Terakado, A., Togo, S., Yamashita, S., and Yoshimoto, T.

Abstract

In this paper, the detailed results of the effect of additional plasma heating under the condition of plasma detachment produced in the large tandem mirror GAMMA 10/PDX. In this experiment, the ECH pulse of 150 kW was applied to the upstream region of detached plasmas established by injecting heavy noble gases (Ar, Kr and Xe) and the significant phenomena on detached to attached transition were measured with Langmuir probes, calorimeters, spectrometers and a high-speed camera. In the presentation, detailed behavior of the plasma parameters is described and the effect of ECH is discussed in terms of radiation loss power and ionization and recombination processes. During the plasma detachment experiments by impurity gas seeding, a short pulse (25 ms) of ECH was applied at the east plug/barriercell to examine the effects of ECH on the detached plasma. A brief summary of the outcomes is given below: ECH heating pulse significantly increases the heat flux at the west end-cell, which indicates detached to attached transition phenomena. During ECH injection period, the ion flux also increases with the increasing gas injection. The emission from the impurity ion enhances significantly during ECH injection period. The emission intensity captured with fast camera also shows a clear dependence on the gas throughput of N2 gas. Comparison of the results using light impurities (N2 and Ne) to those by a heavy impurity gas (Ar) indicates that detached plasma with N2 seeding has a certain tolerance for the additional heating. These outcomes also indicate to consider the sustainability of the detached plasma during ELM., The 23rd International Conference on Plasma Surface Interactions in Controlled Fusion Devices (PSI-23)

Published
2018

31. 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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32. Suppression of flute-like fluctuation by potential formation in GAMMA 10/PDX

Author

Yoshikawa, M., primary, Kohagura, J., additional, Ikezoe, R., additional, Sakamoto, M., additional, Ezumi, N., additional, Minami, R., additional, Hirata, M., additional, Terakado, A., additional, Nojiri, K., additional, Jang, S., additional, Tanaka, A., additional, Ichimura, M., additional, Imai, T., additional, and Nakashima, Y., additional

Published
2019
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33. Synergistic effect of nitrogen and hydrogen seeding gases on plasma detachment in the GAMMA 10/PDX tandem mirror

Author

Ezumi, N., primary, Iijima, T., additional, Sakamoto, M., additional, Nakashima, Y., additional, Hirata, M., additional, Ichimura, M., additional, Ikezoe, R., additional, Imai, T., additional, Kariya, T., additional, Katanuma, I., additional, Kohagura, J., additional, Minami, R., additional, Numakura, T., additional, Yoshikawa, M., additional, Togo, S., additional, Islam, M.S., additional, Islam, M.M., additional, Nojiri, K., additional, Terakado, A., additional, Jang, S., additional, Kinoshita, Y., additional, Mikami, T., additional, Yamashita, S., additional, Yoshimoto, T., additional, Hara, T., additional, Hatayama, A., additional, Ichimura, K., additional, Kado, S., additional, Masuzaki, S., additional, Nakano, T., additional, Ohno, N., additional, Sawada, S., additional, Tanaka, H., additional, Tonegawa, A., additional, and Perillo, R., additional

Published
2019
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38. Recent Progress of Divertor Simulation Research Using the GAMMA 10/PDX Tandem Mirror

Author

Nakashima, Y., Ichimura, K., S., Islan M., Sakamoto, M., Ezumi, N., Hirata, M., Ichimura, M., Ikezoe, R., Imai, T., Kariya, T., Katanuma, I., Kohagura, J., Minami, R., Numakura, T., Yoshikawa, M., M., Islam M., Nojiri, K., Shimizu, K., Terakado, A., Asakura, Nobuyuki, Fukumoto, Masakatsu, Hatayama, A., Hirooka, Y., Kado, S., Kubo, Hirotaka, Masuzaki, S., Matsuura, H., Nakano, Tomohide, Nagata, S., Nishino, N., Ohno, N., Sagara, A., Sawada, K., Shoji, M., Tonegawa, A., and Ueda, Y.

Abstract

This paper describes the characteristics of detached plasma produced by using hydrogen and noble gases together with the progress of high-heat and particle flux generation experiments in the GAMMA 10/PDX end-cell. In the Plasma Research Center, University of Tsukuba, divertor simulation experiments have been started at the end-cell of GAMMA 10/PDX (E-divertor). In the GAMMA 10/PDX end-cell, plasma flow with high temperature (Ti=100–400 eV, Te=30 eV), heat and particle fluxes (>10 MW/m2, >1023/m2s, respectively) have been produced under the high magnetic field (~1T), which cannot be attained by conventional liner devices. We have succeeded in achieving detachment of high temperature plasma equivalent to the SOL plasma of tokamaks in spite of using a linear device with short connection length of magnetic field line. Various gases (N2, Ne, Ar, Xe) are examined to evaluate the effect of radiation cooling against the plasma flow of MW/m2 level in a divertor simulation region and the following results are obtained: i) Xe gas was most effective on electron cooling (down to ~2 eV) and reduction of heat and particle fluxes (1%, 3%, respectively). ii) Ne gas was less effective. On the other hand, iii) N2 gas showed more favourable effects than Ar. The above results are almost consistent with the observation from an absolutely calibrated visible spectrometer viewing the inside of D-module, such as i) stronger emission from Xe I and II, ii) significant molecular visible-emission from N2, etc. Furthermore, in the case with a simultaneous injection of hydrogen and Xe gases, the ion flux was almost fully suppressed, which indicates the existence of molecular activated recombination in D-module. In plasma flow generation experiments, ICRF heating in anchor-cell successfully extended the particle flux up to 3.3ˆ1023 /m2s in the end-cell. Superimposing the ECH pulse (380 kWx5 ms) into the ICRF plasma also succeeded in extending the highest heat flux of ~15 MW/m2, which exceeds the ITER divertor heat load in the steady state. These results will contribute to the progress in detached plasma operation and clarification of radiation cooling mechanism towards the development of the future divertor., 26th IAEA Fusion Energy Conference

Published
2016

39. Synergistic effect of nitrogen and hydrogen seeding gases on plasma detachment in the GAMMA 10/PDX tandem mirror

Author

Sakamoto, M., M. Hirata, Ichimura, M., R. Ikezoe, T. Imai, Kariya, T., Katanuma, I., Kohagura, J., Minami, R., Numakura, T., Yoshikawa, M., Togo, S., Islam, M.S., Islam, M.M., Nojiri, K., Terakado, A., Jang, S., Kinoshita, Y., T. Mikami, Yamashita, S., Yoshimoto, T., Hara, T., A. Hatayama, Ichimura, K., S. Kado, S. Masuzaki, Ohno, N., Sawada, S., Tanaka, H., Tonegawa, A., Perillo, R., Esumi, Naomichi, Nakashima , Yosuke, and Nakano, Tomohide

Abstract

GAMMA10/PDX のDモジュール内のプラズマに，水素とともに少量の窒素などの不純物ガスを入射し，それらの非接触プラズマ形成に与える影響を調べた．水素と窒素を同時に入射した場合には，電子密度とイオン束の明らかな減少が観測された．他方，ネオンやアルゴンなどの希ガスを水素とともに入射した場合には，電子密度とイオン束の減少は明らかではなかった．この結果は窒素分子が介在した再結合過程が重要であることを示唆している．

Published
2019

42. Development and application of radar reflectometer using micro to infrared waves

Author

Mase, A., primary, Kogi, Y., additional, Kuwahara, D., additional, Nagayama, Y., additional, Ito, N., additional, Maruyama, T., additional, Ikezi, H., additional, Wang, X., additional, Inutake, M., additional, Tokuzawa, T., additional, Kohagura, J., additional, Yoshikawa, M., additional, Shinohara, S., additional, Suzuki, A., additional, Sakai, F., additional, Yamashika, M., additional, Tobias, B. J., additional, Muscatello, C., additional, Ren, X., additional, Chen, M., additional, Domier, C. W., additional, and Luhmann, N. C., additional

Published
2018
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43. Measurement of ICRF wave propagation using a microwave reflectometer with fast antenna switching on GAMMA 10

Author

Ikezoe, R., primary, Ichimura, M., additional, Itagaki, J., additional, Hirata, M., additional, Sumida, S., additional, Jang, S., additional, Izumi, K., additional, Tanaka, A., additional, Sekine, R., additional, Kubota, Y., additional, Shima, Y., additional, Kohagura, J., additional, Yoshikawa, M., additional, Sakamoto, M., additional, and Nakashima, Y., additional

Published
2017
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44. Recent progress of divertor simulation research using the GAMMA 10/PDX tandem mirror

Author

Nakashima, Y., primary, Ichimura, K., additional, Islam, M.S., additional, Sakamoto, M., additional, Ezumi, N., additional, Hirata, M., additional, Ichimura, M., additional, Ikezoe, R., additional, Imai, T., additional, Kariya, T., additional, Katanuma, I., additional, Kohagura, J., additional, Minami, R., additional, Numakura, T., additional, Yoshikawa, M., additional, Iijima, T., additional, Islam, M.M., additional, Nojiri, K., additional, Shimizu, K., additional, Terakado, A., additional, Togo, S., additional, Asakura, N., additional, Fukumoto, M., additional, Hatayama, A., additional, Hirooka, Y., additional, Kado, S., additional, Kubo, H., additional, Masuzaki, S., additional, Matsuura, H., additional, Nakano, T., additional, Nagata, S., additional, Nishino, N., additional, Ohno, N., additional, Sagara, A., additional, Sawada, K., additional, Shoji, M., additional, Tonegawa, A., additional, and Ueda, Y., additional

Published
2017
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45. Molecular activated recombination in divertor simulation plasma on GAMMA 10/PDX

Author

Sakamoto, M., primary, Terakado, A., additional, Nojiri, K., additional, Ezumi, N., additional, Nakashima, Y., additional, Sawada, K., additional, Ichimura, K., additional, Fukumoto, M., additional, Oki, K., additional, Shimizu, K., additional, Ohno, N., additional, Masuzaki, S., additional, Togo, S., additional, Kohagura, J., additional, and Yoshikawa, M., additional

Published
2017
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46. Multi-point measurement using two-channel reflectometer with antenna switching for study of high-frequency fluctuations in GAMMA 10

Author

Ikezoe, R., primary, Ichimura, M., additional, Okada, T., additional, Itagaki, J., additional, Hirata, M., additional, Sumida, S., additional, Jang, S., additional, Izumi, K., additional, Tanaka, A., additional, Yoshikawa, M., additional, Kohagura, J., additional, Sakamoto, M., additional, and Nakashima, Y., additional

Published
2017
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47. 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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48. A theory on the x-ray sensitivity of a silicon surface-barrier detector including a thermal charge-diffusion effect.

Author

Cho, T., Hirata, M., Takahashi, E., Teraji, T., Yamaguchi, N., Matsuda, K., Takeuchi, A., Kohagura, J., Ogura, K., Kondoh, T., Osawa, A., Yatsu, K., Tamano, T., and Miyoshi, S.

Subjects
SILICON, X-ray spectroscopy, DETECTORS
Abstract

Presents a study which proposed an analytical method based on a theoretical model for the x-ray energy responses of silicon surface-barrier detectors (SSB). Description of the model used in the study; Formulas and calculated results supporting SSB calibration data; Discussion of results.

Published
1992
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49. Calibration experiments of [sup 3]He neutron detectors for analyzing neutron emissivity in the hot-ion mode on the GAMMA 10 tandem mirror

Author

Kohagura, J., Cho, T., Hirata, M., Watanabe, H., Minami, R., Numakura, T., Yoshida, M., Ito, H., Tatematsu, Y., Yatsu, K., Miyoshi, S., Ogura, K., Kondoh, T., Nishitani, T., Kwon, M., and England, A.C.

Abstract

Under the international fusion cooperating research, ³He neutron detectors in the GAMMA 10 tandem mirror are calibrated by the use of a [sup 252]Cf spontaneous fission neutron source (8.96 × 10[sup 4]n/s). The calibration experiments are carried out with a "rail system" placed along the magnetic axis of the GAMMA 10 central-cell region, where hot ions in the plasma experiments with the bulk temperatures of ∼10 keV are produced. As compared to a previous neutron monitoring system with a BF[sub 3] detector in GAMMA 10, the present ³He systems are designed with about two orders-of-magnitude higher neutron-counting efficiency for analyzing a neutron emissivity from the plasmas in a single plasma discharge alone. Two ³He systems are installed near the middle and the end of the central cell so as to identify the central-cell hot-ion axial profile. The filling pressure of ³He, the effective length, and the diameter of the detector are designed as 5 bar, 300 mm, and 50 mm, respectively. The detector output spectra are carefully analyzed by the use of a preamplifier, a shaping amplifier, as well as a multichannel analyzer for each ³He detector. In the present article, the neutron-counting data from the two ³He detectors due to the on-axis [sup 252]Cf scan are interpreted in terms of the d[sup -2] intensity dependence (d being the distance between the detector and the neutron source) as well as the effects of the central-cell magnetic coils and the other machine structural components.

Published
2003

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