Energy confinement and thermal transport characteristics of net current free plasmas in the large helical device

H. Yamada; K. Y. Watanabe; K. Yamazaki; S. Murakami; S. Sakakibara; K. Narihara; K. Tanaka; M. Osakabe; K. Ida; N. Ashikawa; P. C. De Vries; M. Emoto; H. Funaba; M. Goto; H. Idei; K. Ikeda; S. Inagaki; N. Inoue; M. Isobe; S. Kado; O. Kaneko; K. Kawahata; K. Khlopenkov; T. Kobuchi; A. Komori; S. Kubo; R. Kumazawa; Y. Liang; S. Masuzaki; T. Minami; J. Miyazawa; T. Morisaki; S. Morita; S. Muto; T. Mutoh; Y. Nagayama; N. Nakajima; Y. Nakamura; H. Nakanishi; K. Nishimura; N. Noda; T. Notake; S. Ohdachi; N. Ohyabu; Y. Oka; T. Ozaki; R. O. Pavlichenko; B. J. Peterson; G. Rewoldt; A. Sagara; K. Saito; R. Sakamoto; H. Sasao; M. Sasao; K. Sato; M. Sato; T. Seki; T. Shimozuma; M. Shoji; H. Sugama; H. Suzuki; M. Takechi; Y. Takeiri; N. Tamura; K. Toi; T. Tokuzawa; Y. Torii; K. Tsumori; I. Yamada; S. Yamaguchi; S. Yamamoto; M. Yokoyama; Y. Yoshimura; T. Watari; K. Itoh; K. Matsuoka; K. Ohkubo; I. Ohtake; S. Satoh; T. Satow; S. Sudo; S. Tanahashi; T. Uda; Y. Hamada; O. Motojima; M. Fujiwara

doi:10.1088/0029-5515/41/7/311

Energy confinement and thermal transport characteristics of net current free plasmas in the large helical device

H. Yamada, K. Y. Watanabe, K. Yamazaki, S. Murakami, S. Sakakibara, K. Narihara, K. Tanaka, M. Osakabe, K. Ida, N. Ashikawa, P. C. De Vries, M. Emoto, H. Funaba, M. Goto, H. Idei, K. Ikeda, S. Inagaki, N. Inoue, M. Isobe, S. KadoO. Kaneko, K. Kawahata, K. Khlopenkov, T. Kobuchi, A. Komori, S. Kubo, R. Kumazawa, Y. Liang, S. Masuzaki, T. Minami, J. Miyazawa, T. Morisaki, S. Morita, S. Muto, T. Mutoh, Y. Nagayama, N. Nakajima, Y. Nakamura, H. Nakanishi, K. Nishimura, N. Noda, T. Notake, S. Ohdachi, N. Ohyabu, Y. Oka, T. Ozaki, R. O. Pavlichenko, B. J. Peterson, G. Rewoldt, A. Sagara, K. Saito, R. Sakamoto, H. Sasao, M. Sasao, K. Sato, M. Sato, T. Seki, T. Shimozuma, M. Shoji, H. Sugama, H. Suzuki, M. Takechi, Y. Takeiri, N. Tamura, K. Toi, T. Tokuzawa, Y. Torii, K. Tsumori, I. Yamada, S. Yamaguchi, S. Yamamoto, M. Yokoyama, Y. Yoshimura, T. Watari, K. Itoh, K. Matsuoka, K. Ohkubo, I. Ohtake, S. Satoh, T. Satow, S. Sudo, S. Tanahashi, T. Uda, Y. Hamada, O. Motojima, M. Fujiwara

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Abstract

The energy confinement and thermal transport characteristics of net current free plasmas in regimes with much smaller gyroradii and collisionality than previously studied have been investigated in the Large Helical Device (LHD). The inward shifted configuration, which is superior from the point of view of neoclassical transport theory, has revealed a systematic confinement improvement over the standard configuration. Energy confinement times are improved over the International Stellarator Scaling 95 by a factor of 1.6 ± 0.2 for an inward shifted configuration. This enhancement is primarily due to the broad temperature profile with a high edge value. A simple dimensional analysis involving LHD and other medium sized heliotrons yields a strongly gyro-Bohm dependence (τ_EΩ ∝ ρ*^-3.8) of energy confinement times. It should be noted that this result is attributed to a comprehensive treatment of LHD for systematic confinement enhancement and that the medium sized heliotrons have narrow temperature profiles. The core stored energy still indicates a dependence of τ_EΩ ∝ ρ*^-2.6 when data only from LHD are processed. The local heat transport analysis of discharges dimensionally similar except for ρ* suggests that the heat conduction coefficient lies between Bohm and gyro-Bohm in the core and changes towards strong gyro-Bohm in the peripheral region. Since the inward shifted configuration has a geometrical feature suppressing neoclassical transport, confinement improvement can be maintained in the collisionless regime where ripple transport is important. The stiffness of the pressure profile coincides with enhanced transport in the peaked density profile obtained by pellet injection.

Original language	English
Pages (from-to)	901-908
Number of pages	8
Journal	Nuclear Fusion
Volume	41
Issue number	7
DOIs	https://doi.org/10.1088/0029-5515/41/7/311
Publication status	Published - Jul 2001
Externally published	Yes

All Science Journal Classification (ASJC) codes

Nuclear and High Energy Physics
Condensed Matter Physics

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10.1088/0029-5515/41/7/311

Cite this

Yamada, H., Watanabe, K. Y., Yamazaki, K., Murakami, S., Sakakibara, S., Narihara, K., Tanaka, K., Osakabe, M., Ida, K., Ashikawa, N., De Vries, P. C., Emoto, M., Funaba, H., Goto, M., Idei, H., Ikeda, K., Inagaki, S., Inoue, N., Isobe, M., ... Fujiwara, M. (2001). Energy confinement and thermal transport characteristics of net current free plasmas in the large helical device. Nuclear Fusion, 41(7), 901-908. https://doi.org/10.1088/0029-5515/41/7/311

Yamada, H, Watanabe, KY, Yamazaki, K, Murakami, S, Sakakibara, S, Narihara, K, Tanaka, K, Osakabe, M, Ida, K, Ashikawa, N, De Vries, PC, Emoto, M, Funaba, H, Goto, M, Idei, H, Ikeda, K, Inagaki, S, Inoue, N, Isobe, M, Kado, S, Kaneko, O, Kawahata, K, Khlopenkov, K, Kobuchi, T, Komori, A, Kubo, S, Kumazawa, R, Liang, Y, Masuzaki, S, Minami, T, Miyazawa, J, Morisaki, T, Morita, S, Muto, S, Mutoh, T, Nagayama, Y, Nakajima, N, Nakamura, Y, Nakanishi, H, Nishimura, K, Noda, N, Notake, T, Ohdachi, S, Ohyabu, N, Oka, Y, Ozaki, T, Pavlichenko, RO, Peterson, BJ, Rewoldt, G, Sagara, A, Saito, K, Sakamoto, R, Sasao, H, Sasao, M, Sato, K, Sato, M, Seki, T, Shimozuma, T, Shoji, M, Sugama, H, Suzuki, H, Takechi, M, Takeiri, Y, Tamura, N, Toi, K, Tokuzawa, T, Torii, Y, Tsumori, K, Yamada, I, Yamaguchi, S, Yamamoto, S, Yokoyama, M, Yoshimura, Y, Watari, T, Itoh, K, Matsuoka, K, Ohkubo, K, Ohtake, I, Satoh, S, Satow, T, Sudo, S, Tanahashi, S, Uda, T, Hamada, Y, Motojima, O & Fujiwara, M 2001, 'Energy confinement and thermal transport characteristics of net current free plasmas in the large helical device', Nuclear Fusion, vol. 41, no. 7, pp. 901-908. https://doi.org/10.1088/0029-5515/41/7/311

@article{cbb20ec786784c9f90cd14cdd07bbe65,

title = "Energy confinement and thermal transport characteristics of net current free plasmas in the large helical device",

abstract = "The energy confinement and thermal transport characteristics of net current free plasmas in regimes with much smaller gyroradii and collisionality than previously studied have been investigated in the Large Helical Device (LHD). The inward shifted configuration, which is superior from the point of view of neoclassical transport theory, has revealed a systematic confinement improvement over the standard configuration. Energy confinement times are improved over the International Stellarator Scaling 95 by a factor of 1.6 ± 0.2 for an inward shifted configuration. This enhancement is primarily due to the broad temperature profile with a high edge value. A simple dimensional analysis involving LHD and other medium sized heliotrons yields a strongly gyro-Bohm dependence (τEΩ ∝ ρ*-3.8) of energy confinement times. It should be noted that this result is attributed to a comprehensive treatment of LHD for systematic confinement enhancement and that the medium sized heliotrons have narrow temperature profiles. The core stored energy still indicates a dependence of τEΩ ∝ ρ*-2.6 when data only from LHD are processed. The local heat transport analysis of discharges dimensionally similar except for ρ* suggests that the heat conduction coefficient lies between Bohm and gyro-Bohm in the core and changes towards strong gyro-Bohm in the peripheral region. Since the inward shifted configuration has a geometrical feature suppressing neoclassical transport, confinement improvement can be maintained in the collisionless regime where ripple transport is important. The stiffness of the pressure profile coincides with enhanced transport in the peaked density profile obtained by pellet injection.",

author = "H. Yamada and Watanabe, {K. Y.} and K. Yamazaki and S. Murakami and S. Sakakibara and K. Narihara and K. Tanaka and M. Osakabe and K. Ida and N. Ashikawa and {De Vries}, {P. C.} and M. Emoto and H. Funaba and M. Goto and H. Idei and K. Ikeda and S. Inagaki and N. Inoue and M. Isobe and S. Kado and O. Kaneko and K. Kawahata and K. Khlopenkov and T. Kobuchi and A. Komori and S. Kubo and R. Kumazawa and Y. Liang and S. Masuzaki and T. Minami and J. Miyazawa and T. Morisaki and S. Morita and S. Muto and T. Mutoh and Y. Nagayama and N. Nakajima and Y. Nakamura and H. Nakanishi and K. Nishimura and N. Noda and T. Notake and S. Ohdachi and N. Ohyabu and Y. Oka and T. Ozaki and Pavlichenko, {R. O.} and Peterson, {B. J.} and G. Rewoldt and A. Sagara and K. Saito and R. Sakamoto and H. Sasao and M. Sasao and K. Sato and M. Sato and T. Seki and T. Shimozuma and M. Shoji and H. Sugama and H. Suzuki and M. Takechi and Y. Takeiri and N. Tamura and K. Toi and T. Tokuzawa and Y. Torii and K. Tsumori and I. Yamada and S. Yamaguchi and S. Yamamoto and M. Yokoyama and Y. Yoshimura and T. Watari and K. Itoh and K. Matsuoka and K. Ohkubo and I. Ohtake and S. Satoh and T. Satow and S. Sudo and S. Tanahashi and T. Uda and Y. Hamada and O. Motojima and M. Fujiwara",

year = "2001",

month = jul,

doi = "10.1088/0029-5515/41/7/311",

language = "English",

volume = "41",

pages = "901--908",

journal = "Nuclear Fusion",

issn = "0029-5515",

publisher = "IOP Publishing Ltd.",

number = "7",

}

TY - JOUR

T1 - Energy confinement and thermal transport characteristics of net current free plasmas in the large helical device

AU - Yamada, H.

AU - Watanabe, K. Y.

AU - Yamazaki, K.

AU - Murakami, S.

AU - Sakakibara, S.

AU - Narihara, K.

AU - Tanaka, K.

AU - Osakabe, M.

AU - Ida, K.

AU - Ashikawa, N.

AU - De Vries, P. C.

AU - Emoto, M.

AU - Funaba, H.

AU - Goto, M.

AU - Idei, H.

AU - Ikeda, K.

AU - Inagaki, S.

AU - Inoue, N.

AU - Isobe, M.

AU - Kado, S.

AU - Kaneko, O.

AU - Kawahata, K.

AU - Khlopenkov, K.

AU - Kobuchi, T.

AU - Komori, A.

AU - Kubo, S.

AU - Kumazawa, R.

AU - Liang, Y.

AU - Masuzaki, S.

AU - Minami, T.

AU - Miyazawa, J.

AU - Morisaki, T.

AU - Morita, S.

AU - Muto, S.

AU - Mutoh, T.

AU - Nagayama, Y.

AU - Nakajima, N.

AU - Nakamura, Y.

AU - Nakanishi, H.

AU - Nishimura, K.

AU - Noda, N.

AU - Notake, T.

AU - Ohdachi, S.

AU - Ohyabu, N.

AU - Oka, Y.

AU - Ozaki, T.

AU - Pavlichenko, R. O.

AU - Peterson, B. J.

AU - Rewoldt, G.

AU - Sagara, A.

AU - Saito, K.

AU - Sakamoto, R.

AU - Sasao, H.

AU - Sasao, M.

AU - Sato, K.

AU - Sato, M.

AU - Seki, T.

AU - Shimozuma, T.

AU - Shoji, M.

AU - Sugama, H.

AU - Suzuki, H.

AU - Takechi, M.

AU - Takeiri, Y.

AU - Tamura, N.

AU - Toi, K.

AU - Tokuzawa, T.

AU - Torii, Y.

AU - Tsumori, K.

AU - Yamada, I.

AU - Yamaguchi, S.

AU - Yamamoto, S.

AU - Yokoyama, M.

AU - Yoshimura, Y.

AU - Watari, T.

AU - Itoh, K.

AU - Matsuoka, K.

AU - Ohkubo, K.

AU - Ohtake, I.

AU - Satoh, S.

AU - Satow, T.

AU - Sudo, S.

AU - Tanahashi, S.

AU - Uda, T.

AU - Hamada, Y.

AU - Motojima, O.

AU - Fujiwara, M.

PY - 2001/7

Y1 - 2001/7

N2 - The energy confinement and thermal transport characteristics of net current free plasmas in regimes with much smaller gyroradii and collisionality than previously studied have been investigated in the Large Helical Device (LHD). The inward shifted configuration, which is superior from the point of view of neoclassical transport theory, has revealed a systematic confinement improvement over the standard configuration. Energy confinement times are improved over the International Stellarator Scaling 95 by a factor of 1.6 ± 0.2 for an inward shifted configuration. This enhancement is primarily due to the broad temperature profile with a high edge value. A simple dimensional analysis involving LHD and other medium sized heliotrons yields a strongly gyro-Bohm dependence (τEΩ ∝ ρ*-3.8) of energy confinement times. It should be noted that this result is attributed to a comprehensive treatment of LHD for systematic confinement enhancement and that the medium sized heliotrons have narrow temperature profiles. The core stored energy still indicates a dependence of τEΩ ∝ ρ*-2.6 when data only from LHD are processed. The local heat transport analysis of discharges dimensionally similar except for ρ* suggests that the heat conduction coefficient lies between Bohm and gyro-Bohm in the core and changes towards strong gyro-Bohm in the peripheral region. Since the inward shifted configuration has a geometrical feature suppressing neoclassical transport, confinement improvement can be maintained in the collisionless regime where ripple transport is important. The stiffness of the pressure profile coincides with enhanced transport in the peaked density profile obtained by pellet injection.

AB - The energy confinement and thermal transport characteristics of net current free plasmas in regimes with much smaller gyroradii and collisionality than previously studied have been investigated in the Large Helical Device (LHD). The inward shifted configuration, which is superior from the point of view of neoclassical transport theory, has revealed a systematic confinement improvement over the standard configuration. Energy confinement times are improved over the International Stellarator Scaling 95 by a factor of 1.6 ± 0.2 for an inward shifted configuration. This enhancement is primarily due to the broad temperature profile with a high edge value. A simple dimensional analysis involving LHD and other medium sized heliotrons yields a strongly gyro-Bohm dependence (τEΩ ∝ ρ*-3.8) of energy confinement times. It should be noted that this result is attributed to a comprehensive treatment of LHD for systematic confinement enhancement and that the medium sized heliotrons have narrow temperature profiles. The core stored energy still indicates a dependence of τEΩ ∝ ρ*-2.6 when data only from LHD are processed. The local heat transport analysis of discharges dimensionally similar except for ρ* suggests that the heat conduction coefficient lies between Bohm and gyro-Bohm in the core and changes towards strong gyro-Bohm in the peripheral region. Since the inward shifted configuration has a geometrical feature suppressing neoclassical transport, confinement improvement can be maintained in the collisionless regime where ripple transport is important. The stiffness of the pressure profile coincides with enhanced transport in the peaked density profile obtained by pellet injection.

UR - http://www.scopus.com/inward/record.url?scp=0035412699&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035412699&partnerID=8YFLogxK

U2 - 10.1088/0029-5515/41/7/311

DO - 10.1088/0029-5515/41/7/311

M3 - Article

AN - SCOPUS:0035412699

SN - 0029-5515

VL - 41

SP - 901

EP - 908

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 7

ER -

Energy confinement and thermal transport characteristics of net current free plasmas in the large helical device

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