Power Absorption Calculation for Electron Cyclotron Resonance Heating in H-1 Heliac

Nagasaki, K.; Shats, Michael; Smith, Helen; Punzmann, Horst

doi:10.1143/jpsj.70.617

Cited by 4 publications

(4 citation statements)

References 11 publications

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“…Once it enters the plasma, the differential equations are numerically solved using the dispersion relation (4) by the Hamming method. This calculation method is the same as a ray tracing code for the H-1 heliac device [11]. When the ray reaches the O-mode cut-off layer with optimal angle, it is converted into the X-mode propagating inside the cut-off layer.…”

Section: Ray Tracing Calculation Methodsmentioning

confidence: 99%

Electron Bernstein wave heating in heliotron configurations

Nagasaki

Yanagi

2002

Plasma Phys. Control. Fusion

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Electron Bernstein wave heating is calculated for conventional heliotron configurations by using a ray tracing numerical code in which three-dimensional magnetic field structure is considered. The ordinary (O)-extraordinary (X)electron Bernstein (B) and X-B conversions are treated. In the O-X-B heating, since the magnetic shear is strong and the poloidal field is comparable with the toroidal one, the launching angle should be adjusted both toroidally and poloidally for optimum O-X conversion. The calculation has shown that the power absorption is strongly Doppler shifted due to the large parallel refractive index caused by the inhomogeneity of the magnetic field. The absorption position is weakly dependent on the electron density and temperature, and it can be controlled by changing the magnetic field strength. The slow X-B heating is also possible by launching the X-mode from the vacuum chamber port located at the low-field side because of the three-dimensional magnetic field structures in heliotron configurations. The accessible window in launching angle is rather wide, and the power absorption can be controlled from on-axis to off-axis, which depends on the launching angle, magnetic field and electron density.

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Section: Ray Tracing Calculation Methodsmentioning

confidence: 99%

Electron Bernstein wave heating in heliotron configurations

Nagasaki

Yanagi

2002

Plasma Phys. Control. Fusion

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“…In order to gain the radius and thickness of the resonance layer, the interaction between ECW and HL-2A plasma has been simulated using TORAY ray-tracing code. 39 The calculated results show that r EC = 0.015 m and ⌬ EC = 0.015 m. It follows that the power of ECW is deposited in the plasma center and the resonance layer is very thin. According to these parameters and Eq.…”

Section: Experimental Results and Theoretical Analysesmentioning

confidence: 83%

Enhanced production of runaway electrons during electron cyclotron resonance heating and in the presence of supersonic molecular beam injection in the HL-2A tokamak

Zhang¹,

Liu²,

Yang³

et al. 2010

Physics of Plasmas

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In the present paper, it is reported that a large production of runaway electrons has been observed during the flattop phase of electron cyclotron resonance heating ͑ECRH͒ discharges and in the presence of supersonic molecular beam injection ͑SMBI͒ in the HuanLiuqi-2A ͑commonly referred to as HL-2A͒ ͓Q. W. Yang, Nucl. Fusion 47, S635 ͑2007͔͒ tokamak. For the set of discharges carried out in the present experiment, the ranges of ECRH power and plasma electron density are 0.8-1.0 MW and ͑3.0-4.0͒ ϫ 10 19 m −3 , respectively. A large number of superthermal electrons are produced through the avalanche effect ͓A. Lazaros, Phys. Plasmas 8, 1263 ͑2001͔͒ during ECRH. The loop voltage increase due to SMBI gives rise to a decline in the critical runaway energy, which leads to that many superthermal electrons could be converted into runaway region. Therefore, this phenomenon may come from the synergetic effects of ECRH and SMBI. That is, the superthermal electrons created by ECRH are accelerated into runaway regime via the Dreicer process which is triggered by SMBI. The experimental results are in well agreement with the calculational ones based on the superthermal electron avalanche effect and the Dreicer runaway theory.

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“…Incidentally, in the theoretical simulations of the fusion plasma, one should specify the beam profile for the beam absorption power, which has the inherent limitations to describe the complex events. Therefore, we end up with a simplified method model as a Gaussian beam profile [16,17,30,31].…”

Section: Power Deposition Profiles Near Ecr Frequencymentioning

confidence: 99%

Study Electron Cyclotron Double Mode Conversion in Overdense Plasma

et al. 2019

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Double mode conversion from ordinary mode O to extraordinary mode X is used to achieve electron Bernstein wave (EBWs) for the electron cyclotron resonance heating (ECRH). The efficiency of the mode conversion depends on many parameters including the density gradient L n , magnetic field source B 0 and optimum launching angle N z. An analytical formalism together with a numerical computation have been employed, considering W7X stellarator main parameters, such as 140 GH z , k 0 = 29 cm −1 , 2.5 T and 2.4 ×10 20 m −3 , in order to investigate the efficiency of the mode conversion. The values of the density gradient Ln, obtained by numerical simulation, are from 1 to 10 cm. These values of L n correspond to the power transmission window T OSX from 88 to 29%. Moreover, the dispersion relation of the EBW mode propagation up to 10 harmonics, ω = 10ω ce , has been plotted to help a better visualization of the EBW mode heating. Finally, the power deposition profiles around the resonance layers were calculated and presented.

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Power Absorption Calculation for Electron Cyclotron Resonance Heating in H-1 Heliac

Cited by 4 publications

References 11 publications

Electron Bernstein wave heating in heliotron configurations

Electron Bernstein wave heating in heliotron configurations

Enhanced production of runaway electrons during electron cyclotron resonance heating and in the presence of supersonic molecular beam injection in the HL-2A tokamak

Study Electron Cyclotron Double Mode Conversion in Overdense Plasma

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