Observation of inward turbulent particle transport in edge plasma region of CHS heliotron/torsatron

K. Toi; K. Ohkuni; M. G. Shats; R. Akiyama; M. Goto; M. Isobe; G. Matsunaga; K. Matsuoka; T. Minami; S. Morita; S. Nishimura; I. Nomura; S. Okamura; M. Osakabe; A. Shimizu; C. Suzuki; S. Takagi; C. Takahashi; M. Takechi; K. Tanaka; Y. Yoshimura

doi:10.1088/0741-3335/44/5A/323

Observation of inward turbulent particle transport in edge plasma region of CHS heliotron/torsatron

K. Toi^*, K. Ohkuni, M. G. Shats, R. Akiyama, M. Goto, M. Isobe, G. Matsunaga, K. Matsuoka, T. Minami, S. Morita, S. Nishimura, I. Nomura, S. Okamura, M. Osakabe, A. Shimizu, C. Suzuki, S. Takagi, C. Takahashi, M. Takechi, K. TanakaY. Yoshimura

^*Corresponding author for this work

Research output: Contribution to journal › Conference article › peer-review

8 Citations (Scopus)

Abstract

Reversal of turbulent particle flux near the plasma edge of CHS heliotron/torsatron was observed on various discharge conditions, i.e. during tangential neutral beam injection, electron cyclotron heating at the far edge, and the sawtooth crash. For all cases, the reversal is realized at a narrow particular layer near the plasma edge, when plasma parameters go into low collisionality. The reversal is caused by the change in the cross phase between density (n_e) and poloidal electric field (E_θ) fluctuations. The turbulent flux is always inward when the radial electric field shear (E′_r) exceeds a certain threshold of ∼1 × 10⁶V m^-2. In the sawtoothing plasmas, the arrival of a heat pulse due to the sawtooth crash enhances both n_e and E_θ fluctuations but changes the cross phase to π in low-frequency range. As a result, a large inward flux is generated by the sawtooth crash. The particle flux reversal in these cases did not lead to obvious confinement improvement.

Original language	English
Article number	323
Pages (from-to)	A237-A243
Journal	Plasma Physics and Controlled Fusion
Volume	44
Issue number	5 A
DOIs	https://doi.org/10.1088/0741-3335/44/5A/323
Publication status	Published - May 2002
Event	8th IAEA Technical Committee Meeting on H-Mode Physics and Transport Barriers - Toki, Japan Duration: 5 Sept 2001 → 7 Sept 2001

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Toi, K., Ohkuni, K., Shats, M. G., Akiyama, R., Goto, M., Isobe, M., Matsunaga, G., Matsuoka, K., Minami, T., Morita, S., Nishimura, S., Nomura, I., Okamura, S., Osakabe, M., Shimizu, A., Suzuki, C., Takagi, S., Takahashi, C., Takechi, M., ... Yoshimura, Y. (2002). Observation of inward turbulent particle transport in edge plasma region of CHS heliotron/torsatron. Plasma Physics and Controlled Fusion, 44(5 A), A237-A243. Article 323. https://doi.org/10.1088/0741-3335/44/5A/323

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title = "Observation of inward turbulent particle transport in edge plasma region of CHS heliotron/torsatron",

abstract = "Reversal of turbulent particle flux near the plasma edge of CHS heliotron/torsatron was observed on various discharge conditions, i.e. during tangential neutral beam injection, electron cyclotron heating at the far edge, and the sawtooth crash. For all cases, the reversal is realized at a narrow particular layer near the plasma edge, when plasma parameters go into low collisionality. The reversal is caused by the change in the cross phase between density (ne) and poloidal electric field (Eθ) fluctuations. The turbulent flux is always inward when the radial electric field shear (E′r) exceeds a certain threshold of ∼1 × 106V m-2. In the sawtoothing plasmas, the arrival of a heat pulse due to the sawtooth crash enhances both ne and Eθ fluctuations but changes the cross phase to π in low-frequency range. As a result, a large inward flux is generated by the sawtooth crash. The particle flux reversal in these cases did not lead to obvious confinement improvement.",

author = "K. Toi and K. Ohkuni and Shats, \{M. G.\} and R. Akiyama and M. Goto and M. Isobe and G. Matsunaga and K. Matsuoka and T. Minami and S. Morita and S. Nishimura and I. Nomura and S. Okamura and M. Osakabe and A. Shimizu and C. Suzuki and S. Takagi and C. Takahashi and M. Takechi and K. Tanaka and Y. Yoshimura",

year = "2002",

month = may,

doi = "10.1088/0741-3335/44/5A/323",

language = "English",

volume = "44",

pages = "A237--A243",

journal = "Plasma Physics and Controlled Fusion",

issn = "0741-3335",

publisher = "IOP Publishing Ltd.",

number = "5 A",

note = "8th IAEA Technical Committee Meeting on H-Mode Physics and Transport Barriers ; Conference date: 05-09-2001 Through 07-09-2001",

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Toi, K, Ohkuni, K, Shats, MG, Akiyama, R, Goto, M, Isobe, M, Matsunaga, G, Matsuoka, K, Minami, T, Morita, S, Nishimura, S, Nomura, I, Okamura, S, Osakabe, M, Shimizu, A, Suzuki, C, Takagi, S, Takahashi, C, Takechi, M, Tanaka, K & Yoshimura, Y 2002, 'Observation of inward turbulent particle transport in edge plasma region of CHS heliotron/torsatron', Plasma Physics and Controlled Fusion, vol. 44, no. 5 A, 323, pp. A237-A243. https://doi.org/10.1088/0741-3335/44/5A/323

TY - JOUR

T1 - Observation of inward turbulent particle transport in edge plasma region of CHS heliotron/torsatron

AU - Toi, K.

AU - Ohkuni, K.

AU - Shats, M. G.

AU - Akiyama, R.

AU - Goto, M.

AU - Isobe, M.

AU - Matsunaga, G.

AU - Matsuoka, K.

AU - Minami, T.

AU - Morita, S.

AU - Nishimura, S.

AU - Nomura, I.

AU - Okamura, S.

AU - Osakabe, M.

AU - Shimizu, A.

AU - Suzuki, C.

AU - Takagi, S.

AU - Takahashi, C.

AU - Takechi, M.

AU - Tanaka, K.

AU - Yoshimura, Y.

PY - 2002/5

Y1 - 2002/5

N2 - Reversal of turbulent particle flux near the plasma edge of CHS heliotron/torsatron was observed on various discharge conditions, i.e. during tangential neutral beam injection, electron cyclotron heating at the far edge, and the sawtooth crash. For all cases, the reversal is realized at a narrow particular layer near the plasma edge, when plasma parameters go into low collisionality. The reversal is caused by the change in the cross phase between density (ne) and poloidal electric field (Eθ) fluctuations. The turbulent flux is always inward when the radial electric field shear (E′r) exceeds a certain threshold of ∼1 × 106V m-2. In the sawtoothing plasmas, the arrival of a heat pulse due to the sawtooth crash enhances both ne and Eθ fluctuations but changes the cross phase to π in low-frequency range. As a result, a large inward flux is generated by the sawtooth crash. The particle flux reversal in these cases did not lead to obvious confinement improvement.

AB - Reversal of turbulent particle flux near the plasma edge of CHS heliotron/torsatron was observed on various discharge conditions, i.e. during tangential neutral beam injection, electron cyclotron heating at the far edge, and the sawtooth crash. For all cases, the reversal is realized at a narrow particular layer near the plasma edge, when plasma parameters go into low collisionality. The reversal is caused by the change in the cross phase between density (ne) and poloidal electric field (Eθ) fluctuations. The turbulent flux is always inward when the radial electric field shear (E′r) exceeds a certain threshold of ∼1 × 106V m-2. In the sawtoothing plasmas, the arrival of a heat pulse due to the sawtooth crash enhances both ne and Eθ fluctuations but changes the cross phase to π in low-frequency range. As a result, a large inward flux is generated by the sawtooth crash. The particle flux reversal in these cases did not lead to obvious confinement improvement.

UR - https://www.scopus.com/pages/publications/0036573433

U2 - 10.1088/0741-3335/44/5A/323

DO - 10.1088/0741-3335/44/5A/323

M3 - Conference article

SN - 0741-3335

VL - 44

SP - A237-A243

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

IS - 5 A

M1 - 323

T2 - 8th IAEA Technical Committee Meeting on H-Mode Physics and Transport Barriers

Y2 - 5 September 2001 through 7 September 2001

ER -

Observation of inward turbulent particle transport in edge plasma region of CHS heliotron/torsatron

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