Preionization and start-up in the ISX-B tokamak using electron cyclotron heating at 28 GHz

Kulchar, A. G.; Eldridge, O. C.; England, A.C.; Bush, C. E.; Edmonds, P.H.; Kelley, G.G.; Loring, C.M.; Peng, Yueng Kay Martin; Wilgen, J. B.; Borowski, Stanley K.

doi:10.2172/5703037

Cited by 3 publications

(8 citation statements)

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“…Thus, assist of plasma breakdown by ECRH pre-ionization is needed in ITER-like tokamaks. Fundamental ECRH-assisted breakdown has been investigated in many tokamaks [4,5,6,7,8]. Second harmonic ECRH breakdown was also robust in DIII-D [9] and KSTAR [10].…”

Section: Introductionmentioning

confidence: 99%

Electron cyclotron heating during ECRH-assisted pre-ionization in a tokamak

et al. 2010

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In this research, we investigate ECRH for low-energy electrons analytically and numerically, which is applicable to ECRH-assisted plasma start-up in a tokamak. From the previous experimental studies, it is wellknown that the first harmonic ECRH is more effective than the second harmonic ECRH. In this work, we developed an analytic model of ECRH in the start-up process and present comparisons of the efficiency between the first harmonic and the second harmonic. It is found that electrons gain a large energy from the waves at first harmonic resonance up to several hundred eV. However, electrons gain a large energy from the waves only up to ∼10 eV and energy-gain starts decreasing afterward at second harmonic resonance. When seed electrons are heated from the room temperature to far away above the ionization energy, seed electrons can bring about an avalanche of electrons. Thus, pre-ionization with the second harmonic can be delayed since electrons need more time to be heated up to the breakdown temperature due to the slow heating speed compared to the first harmonic ECRH.

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Section: Introductionmentioning

confidence: 99%

Electron cyclotron heating during ECRH-assisted pre-ionization in a tokamak

et al. 2010

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“…The complexity of the plasma expanding in minor radius can be the subject of future studies. Previously, it has also been found [2] that the best results are obtained with a parallel index of refraction, of 0.5 and 100% -mode polarization. This implies that the radiation incident on the plasma either from the high-field side or from the low-field side is transformed by a polarization rotator on the inside wall and reflected back to the plasma as -mode.…”

Section: Introductionmentioning

confidence: 94%

“…While some of the predictions of the theory were not born out by the experiments, nevertheless, the theory was important in showing the value of preionization for voltage reduction. On the basis of the experimental work by Kulchar et al [2], a model was produced which was able to adequately describe the experiments in ISX-B. Later experimental work included the large tokamak experiments in T-10 [3] and DIII-D [4].…”

Section: Introductionmentioning

confidence: 99%

Study of the effects of ECh power and pulse length on preionization in the KSTAR Tokamak

Bae

Namkung²,

Cho

et al. 2003

IEEE Trans. Plasma Sci.

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In this paper, we present the results of a study of the preionization effects for the Korean Superconducting Tokamak Advanced Research (KSTAR) tokamak (0 = 1 8 m, = 0 5 m, = 2 = 0 8 = 3 5 T, = 2 MA, pulse = 300 s) that is under construction by the Korea Basic Science Institute (KBSI). The preionization will be given by the Electron Cyclotron Heating (ECH) System with an 84-GHz 500-kW gyrotron tube being made by Communications and Power Industries. The ECH preionization effects are investigated by a 0-dimensional code (TECHP0D 1) that includes the operational scenarios of KSTAR tokamak. The code is now improved and advanced with carbon, oxygen, and iron impurity effects, and with the self and mutual inductances of seven pairs of superconducting poloidal coils for the KSTAR tokamak. Index Terms-Electron cyclotron heating (ECH), gyrotron, Korean superconducting tokamak advanced research (KSTAR), poloidal, preionization.

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“…Figure 9 shows the electron density and plasma conductivity at the toroidal cross section of plasma, far from filament after a half period of discharge (4.16 × 10 −4 s). The resultant average electron density and conductivity of plasma at the end of pre-ionization process are about 1×10 19 m −3 and 7 × 10 3 s m −1 respectively which are adequate values to start OH discharge (Kirbie 1978;Kulchar et al 1984;Darrow and Ono 1991;Bae and England 2007).…”

Section: Simulation and Design Of Reverse Discharge Loopmentioning

confidence: 99%

“…It is now a common practice to use different advanced methods instead of a hot cathode such as electron cyclotron resonance (Kulchar et al 1984;Bae and England 2007). However, due to some laboratory limitations, the mentioned systems were used in our tokamak.…”

Section: Introductionmentioning

confidence: 99%

Simulation and design of pre-ionization systems for Alborz tokamak

Shahshenas

Amrollahi

2014

J. Plasma Phys.

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Alborz tokamak is an educational system for studying plasma phenomena in many physics and engineering experiments. A hot filament and a reverse discharge loop are used in the tokamak as the pre-ionization system. The hot cathode prepares a local initial electron density, then the reverse discharge loop trigger the ionization avalanche by means of inducing a toroidal electric field. The parameters of the hot filament are determined in order to produce the desired electron source. Filament temperature is simulated by using three-dimensional finite element method. The average values of filament temperature and electron density at the plasma core (at the end of pre-ionization process) were calculated and are about 2750 K and 10 19 m −3 , respectively. The resultant electron density and equivalent plasma resistivity due to reverse discharge loop are also calculated. In this paper, the simulation results, optimum structural style, the obtained parameters, the temperature of different parts of the filament and produced electron density are presented and discussed.

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Preionization and start-up in the ISX-B tokamak using electron cyclotron heating at 28 GHz

Cited by 3 publications

References 0 publications

Electron cyclotron heating during ECRH-assisted pre-ionization in a tokamak

Electron cyclotron heating during ECRH-assisted pre-ionization in a tokamak

Study of the effects of ECh power and pulse length on preionization in the KSTAR Tokamak

Simulation and design of pre-ionization systems for Alborz tokamak

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