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Journal Articles

Role of the electron temperature in the current decay during disruption in JT-60U

Shibata, Yoshihide; Isayama, Akihiko; Matsunaga, Go; Kawano, Yasunori; Miyamoto, Seiji*; Lukash, V.*; Khayrutdinov, R.*; JT-60 Team

Plasma and Fusion Research (Internet), 9(Sp.2), p.3402084_1 - 3402084_5, 2014/06

https://doi.org/10.1585/pfr.9.3402084

We performed the disruption simulation using DINA code to investigate the effect of the electron temperature $T_{rm e}$ on the plasma current decay after the initial phase of current quench (CQ). In this calculation, we used the measured $T_{rm e}$ profile during the initial phase of CQ. After the initial phase of CQ, we assumed that the $T_{rm e}$ profile does not change in time and used the value at the end of the initial phase of current quench because $T_{rm e}$ profile could not be measured after the initial phase of CQ. From the simulation results, it was found that the time evolution of plasma current calculated by DINA was similar to experimental one in this calculation. However, the time evolution of $T_{rm e}$ profile in this calculation was different from the measured $T_{rm e}$ profile because Te after first mini-collapse rapidly decreased until the value below a measurement limit (less than 0.1 keV). Moreover, the time evolution of poloidal cross-section S calculated by DINA code was rapidly decreased although the experimental one was gradually decreased. The plasma current decay during the disruption is determined by various parameters, $dL_{rm p}/dt$ , $T_{rm e}$ and S. It is necessary to evaluate the effect of $T_{rm e}$ profile on the plasma current decay after the initial phase of CQ by using various assumed $T_{rm e}$ model and DINA code.

Journal Articles

The Effect of the electron temperature and current density profiles on the plasma current decay in JT-60U disruptions

Shibata, Yoshihide; Isayama, Akihiko; Miyamoto, Seiji*; Kawakami, Sho*; Watanabe, Kiyomasa*; Matsunaga, Go; Kawano, Yasunori; Lukash, V.*; Khayrutdinov, R.*; JT-60 Team

Plasma Physics and Controlled Fusion, 56(4), p.045008_1 - 045008_8, 2014/04

https://doi.org/10.1088/0741-3335/56/4/045008

Times Cited Count：3 Percentile：13.86(Physics, Fluids & Plasmas)

In JT-60U disruption, the plasma current decay during the initial phase of current quench has been calculated by a disruption simulation code (DINA) using the measured electron temperature $T_{rm e}$ profile. In the case of fast plasma current decay, $T_{rm e}$ has a peaked profile just after thermal quench and the $T_{rm e}$ profile doesn't change significantly during the initial phase of current quench. On the other hand, in the case of the slow plasma current decay, the $T_{rm e}$ profile is border just after the thermal quench, and the $T_{rm e}$ profile shrinks. The results of DINA simulation show that plasma internal inductance $L_{rm i}$ increases during the initial phase of current quench, while plasma external inductance $L_{rm e}$ does not change in time. The increase of $L_{rm i}$ is caused by current diffusion toward the core plasma due to the decrease of $T_{rm e}$ in intermediate and edge regions. It is suggested that an additional heating in the plasma periphery region has the effect of slowing down plasma current decay.

Journal Articles

Effect of resistivity profile on current decay time of initial phase of current quench in neon-gas-puff inducing disruptions of JT-60U

Kawakami, Sho*; Shibata, Yoshihide; Watanabe, Kiyomasa*; Ono, Noriyasu*; Isayama, Akihiko; Takizuka, Tomonori*; Kawano, Yasunori; Okamoto, Masaaki*

Physics of Plasmas, 20(11), p.112507_1 - 112507_6, 2013/11

https://doi.org/10.1063/1.4830103

Times Cited Count：2 Percentile：8.30(Physics, Fluids & Plasmas)

According to an early work on the behavior of the plasma current decay in the JT-60U disruptive discharges caused by the radiative collapse with a massive neon-gas-puff, the increase of the internal inductance mainly determined the current decay time of plasma current during the initial phase of current quench. To investigate what determines the increase of the internal inductance, we focus attention on the relationship between the electron temperature (or the resistivity) profile and the time evolution of the current density profile, and carry out numerical calculations. As a result, we find the reason of the increase of the internal inductance: The current density profile at the start of the current quench is broader than an expected current density profile in the steady state, which is determined by the temperature (or resistivity) profile. The current density profile evolves into peaked one and the internal inductance is increasing.

Journal Articles

Study of plasma current decay in the initial phase of high poloidal beta disruptions in JT-60U

Shibata, Yoshihide*; Watanabe, Kiyomasa*; Ono, Noriyasu*; Okamoto, Masaaki*; Isayama, Akihiko; Kurihara, Kenichi; Oyama, Naoyuki; Nakano, Tomohide; Kawano, Yasunori; Matsunaga, Go; et al.

Plasma and Fusion Research (Internet), 6, p.1302136_1 - 1302136_4, 2011/10

https://doi.org/10.1585/pfr.6.1302136

no abstracts in English

Journal Articles

Study of current decay time during disruption in JT-60U tokamak

Shibata, Yoshihide*; Watanabe, Kiyomasa*; Okamoto, Masaaki*; Ono, Noriyasu*; Isayama, Akihiko; Kurihara, Kenichi; Nakano, Tomohide; Oyama, Naoyuki; Kawano, Yasunori; Matsunaga, Go; et al.

Nuclear Fusion, 50(2), p.025015_1 - 025015_7, 2010/01

https://doi.org/10.1088/0029-5515/50/2/025015

Times Cited Count：17 Percentile：52.23(Physics, Fluids & Plasmas)

no abstracts in English

Oral presentation

Investigation of the influence of plasma inductance in the fast current decay of JT-60U disruptive discharges and verification of the current decay model

Shibata, Yoshihide*; Watanabe, Kiyomasa*; Okamoto, Masaaki*; Ono, Noriyasu*; Isayama, Akihiko; Kurihara, Kenichi; Oyama, Naoyuki; Nakano, Tomohide; Kawano, Yasunori; Matsunaga, Go; et al.

no journal, ,

no abstracts in English

Oral presentation

Comparison of the current decay time during minor collapse and major disruption in high plasma discharges of JT-60U

Shibata, Yoshihide*; Watanabe, Kiyomasa*; Ono, Noriyasu*; Okamoto, Masaaki*; Isayama, Akihiko; Kurihara, Kenichi; Oyama, Naoyuki; Nakano, Tomohide; Kawano, Yasunori; Matsunaga, Go; et al.

no journal, ,

no abstracts in English

Oral presentation

Dependency of plasma parameter against current decay time in JT-60U disruptive discharges

Shibata, Yoshihide; Ide, Shunsuke; Fujita, Takaaki; Isayama, Akihiko; Watanabe, Kiyomasa*; Oyama, Naoyuki; Kurihara, Kenichi; Kawano, Yasunori; Sugihara, Masayoshi*

no journal, ,

no abstracts in English

Oral presentation

Construction and commissioning of a small non-circular tokamak

Hatakeyama, Shoichi*; Miura, Hiromasa*; Yao, Z.*; Tsutsui, Hiroaki*; Iio, Shunji*; Shibata, Yoshihide; Ono, Noriyasu*; Watanabe, Kiyomasa*; Akiyama, Tsuyoshi*; Nakamura, Kazuo*

no journal, ,

no abstracts in English

Oral presentation

Evaluation of current decay time and electron temperature evaluated from He I line intensity ratios during disruption in JT-60U tokamak

Shibata, Yoshihide*; Ono, Noriyasu*; Okamoto, Masaaki*; Nakano, Tomohide; Kawano, Yasunori

no journal, ,

no abstracts in English

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Role of the electron temperature in the current decay during disruption in JT-60U

The Effect of the electron temperature and current density profiles on the plasma current decay in JT-60U disruptions

Effect of resistivity profile on current decay time of initial phase of current quench in neon-gas-puff inducing disruptions of JT-60U

Study of plasma current decay in the initial phase of high poloidal beta disruptions in JT-60U

Study of current decay time during disruption in JT-60U tokamak

Investigation of the influence of plasma inductance in the fast current decay of JT-60U disruptive discharges and verification of the current decay model

Comparison of the current decay time during minor collapse and major disruption in high plasma discharges of JT-60U

Analysis of current quench of the JT-60U tokamak by using two dimensional MHD equilibrium calculation code (DINA)

Study of plasma collapse in plasma current ramp-down phase of tokamak and helical devices

Study of current behavior during current quench of disruption in JT-60U tokamak

Study of plasma current behavior during minor collapse in the JT-60U tokamak

Design and manufacturing of a small VDE-Free tokamak

Effect of interaction between current outside plasma and the MHD equilibrium on the current decay time during the current quench phase in tokamak disruption discharges

A Role of MHD instability against the electron temperature profile during the massive neon gas-puff disruptions in JT-60U

Analysis of current quench induced by the massive neon gas-puff in JT-60U using DINA code

Influence of MHD instability just before disruption on the electron temperature profile after the thermal quench in JT-60U

Verification of the current decay model in the high $_{rm p}$ disruptive discharges in JT-60U

Dependency of plasma parameter against current decay time in JT-60U disruptive discharges

Construction and commissioning of a small non-circular tokamak

Evaluation of current decay time and electron temperature evaluated from He I line intensity ratios during disruption in JT-60U tokamak