Observation of second harmonic electron cyclotron resonance heating and current-drive transition during non-inductive plasma start-up experiment in QUEST

Shinichiro Kojima; Kazuaki Hanada; H Idei; Takumi Onchi; R. Ikezoe; Yoshihiko Nagashima; Makoto Hasegawa; K Kuroda; Kazuo Nakamura; Aki Higashijima; Takahiro Nagata; Shoji Kawasaki; Shun Shimabukuro; Hatem Elserafy; Masaharu Fukuyama; Akira Ejiri; Taiichi Shikama; Nao Yoneda; Ryota Yoneda; Tsuyoshi Kariya; Yuichi Takase; Sadayoshi Murakami; Nicola Bertelli; Masayuki Ono

doi:10.1088/1361-6587/ac1838

journal article Aug 27, 2021

Observation of second harmonic electron cyclotron resonance heating and current-drive transition during non-inductive plasma start-up experiment in QUEST

Shinichiro Kojima

Kazuaki Hanada H Idei

Takumi Onchi R. Ikezoe

Yoshihiko Nagashima Makoto Hasegawa K Kuroda

Kazuo Nakamura Aki Higashijima Takahiro Nagata Shoji Kawasaki Shun Shimabukuro Hatem Elserafy Masaharu Fukuyama Akira Ejiri

Taiichi Shikama

Nao Yoneda Ryota Yoneda Tsuyoshi Kariya Yuichi Takase

Sadayoshi Murakami Nicola Bertelli Masayuki Ono

Plasma Physics and Controlled Fusion Vol. 63 No. 10 pp. 105002 · IOP Publishing

View at Publisher Save 10.1088/1361-6587/ac1838

Abstract

Abstract

Noninductive plasma current start-up using 2nd harmonic electron cyclotron resonance heating (ECRH) with oblique radio frequency (RF) injection is demonstrated in a Q-shu University experiment with steady-state spherical tokamak. A strong transition was observed in the heating and plasma current ramp-up. The initial bulk electron heating regime exhibits
T
ebulk
∼ 140 eV and no hard x-ray (HXR) emission with a low
I
p
of ∼15 kA; it abruptly transitions to a regime that exhibits a low
T
ebulk
of ∼10 eV and a strong HXR emission with a high
I
p
of ∼50 kA. This behavior is distinctly different from that observed in previous fundamental ECRH experiments. The mechanism of the heating and current drive transition are investigated considering wave power absorption and plasma power balance. The results indicate that the transition is caused by the favorable heating of tail electrons where the RF power absorption at the 2nd harmonic increases nearly linearly with
T
etail
, while the power transfer from the tail electrons to the bulk electrons decreases with 1/
T
etail
0.5
. This causes a rapid transition to a state with high
T
etail
while reducing
T
ebulk
towards colder ion temperature. The understanding of the transition mechanism helps to consider plasma current start-up using 2nd harmonic ECRH for tokamak reactors such as JT-60 SA and ITER.

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References

62

[1]

Sykes Plasma Phys. Control. Fusion (1994) 10.1088/0741-3335/36/12b/007

[2]

Kaye Nucl. Fusion (2005) 10.1088/0029-5515/45/10/s14

[3]

Chapman Nucl. Fusion (2015) 10.1088/0029-5515/55/10/104008

[4]

Raman Plasma Phys. Control. Fusion (2014) 10.1088/0741-3335/56/10/103001

[5]

Ono Nucl. Fusion (2003) 10.1088/0029-5515/43/8/321

[6]

Ono Plasma Phys. Control. Fusion (2012) 10.1088/0741-3335/54/12/124039

[7]

Sykes Nucl. Fusion (2001) 10.1088/0029-5515/41/10/310

[8]

Raman Phys. Rev. Lett. (2003) 10.1103/physrevlett.90.075005

[9]

Raman Phys. Rev. Lett. (2010) 10.1103/physrevlett.104.095003

[10]

Nagata Phys. Plasmas (2003) 10.1063/1.1580815

[11]

Kuroda Plasma Fusion Res. (2017) 10.1585/pfr.12.1202020

[12]

Kuroda Plasma Phys. Control. Fusion (2018) 10.1088/1361-6587/aadcb7

[13]

Forest Phys. Plasmas (1994) 10.1063/1.870708

[14]

Tanaka Nucl. Fusion (1993) 10.1088/0029-5515/33/3/i13

[15]

Lloyd Nucl. Fusion (1991) 10.1088/0029-5515/31/11/001

[16]

Shiraiwa Phys. Rev. Lett. (2004) 10.1103/physrevlett.92.035001

[17]

Kirneva "Plasma start-up optimisation with 2nd harmonic ECR pre-ionisation in T-10 tokamak" (2007)

[18]

Borshchegovskiy EPJ Web Conf. (2012) 10.1051/epjconf/20123202004

[19]

Coda Plasma Phys. Control. Fusion (2000) 10.1088/0741-3335/42/12b/323

[20]

Erckmann IEEE Trans. Plasma Sci. (1999) 10.1109/27.772283

[21]

Laqua EPJ Web Conf. (2018) 10.1051/epjconf/201920302002

[22]

Igami EPJ Web Conf. (2019) 10.1051/epjconf/201920302001

[23]

Ejiri Nucl. Fusion (2006) 10.1088/0029-5515/46/7/003

[24]

Yoshinaga Phys. Rev. Lett. (2006) 10.1103/physrevlett.96.125005

[25]

Hanada Plasma Sci. Technol. (2011) 10.1088/1009-0630/13/3/08

[26]

Uchida J. Plasma Fusion Res. (2004) 10.1585/jspf.80.83

[27]

Miura Plasma Fusion Res. (2015) 10.1585/pfr.10.3402066

[28]

Gantenbein Phys. Rev. Lett. (2000) 10.1103/physrevlett.85.1242

[29]

La Haye Phys. Plasmas (2002) 10.1063/1.1456066

[30]

Kong Nucl. Fusion (2019) 10.1088/1741-4326/ab1e1e

[31]

Sakamoto Plasma Phys. Control. Fusion (2006) 10.1088/0741-3335/48/5a/s05

[32]

Vershkov Nucl. Fusion (2017) 10.1088/1741-4326/aa6b0e

[33]

Tanaka Nucl. Fusion (1991) 10.1088/0029-5515/31/9/006

[34]

Jackson Nucl. Fusion (2011) 10.1088/0029-5515/51/8/083015

[35]

Idei (2016)

[36]

Bae Nucl. Fusion (2009) 10.1088/0029-5515/49/2/022001

[37]

Seol Phys. Plasmas (2009) 10.1063/1.3139249

[38]

Seol Nucl. Fusion (2010) 10.1088/0029-5515/50/10/105008

[39]

Idei Nucl. Fusion (2017) 10.1088/1741-4326/aa7c20

[40]

Kajiwara Nucl. Fusion (2005) 10.1088/0029-5515/45/7/019

[41]

Kojima Plasma Fusion Res. (2020) 10.1585/pfr.15.2402063

[42]

Onchi Phys. Plasmas (2021) 10.1063/5.0031357

[43]

Minashin (2014)

[44]

Kobayashi EPJ Web Conf. (2015) 10.1051/epjconf/20158704008

[45]

Stober Nucl. Fusion (2011) 10.1088/0029-5515/51/8/083031

[46]

Henderson Phys. Plasmas (2015) 10.1063/1.4908598

[47]

Idei Fusion Eng. Des. (2019) 10.1016/j.fusengdes.2019.02.027

[48]

Yamaguchi Plasma Fusion Res. (2013) 10.1585/pfr.8.1302001

[49]

Lao Nucl. Fusion (1985) 10.1088/0029-5515/25/10/004

[50]

Xue J. Fusion Energy (2019) 10.1007/s10894-019-00209-5

Showing 50 of 62 references

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Details

Published: Aug 27, 2021
Vol/Issue: 63(10)
Pages: 105002
License: View

Authors

Funding

Japan Society for the Promotion of Science Award: 16H02441

JSPS-NRF-NSFC A3 Foresight Program in the field of Plasma Physics Award: NSFC number 11261140328

NIFS Collaboration Research Program Award: NIFS05KUTRO14

Cite This Article

Shinichiro Kojima, Kazuaki Hanada, H Idei, et al. (2021). Observation of second harmonic electron cyclotron resonance heating and current-drive transition during non-inductive plasma start-up experiment in QUEST. Plasma Physics and Controlled Fusion, 63(10), 105002. https://doi.org/10.1088/1361-6587/ac1838

Observation of second harmonic electron cyclotron resonance heating and current-drive transition during non-inductive plasma start-up experiment in QUEST

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