scholarly journals Gyrotron: The most Suitable Millimeter-Wave Source for Heating of Plasma in Tokamak

2021 ◽  
Author(s):  
Santanu Karmakar ◽  
Jagadish C. Mudiganti
Keyword(s):  
Millimeter Wave ◽  
Electron Cyclotron Resonance ◽  
Plasma Heating ◽  
Electron Cyclotron ◽  
Current Drive ◽  
Electron Cyclotron Resonance Heating ◽  
Wave Source ◽  
Microwave Source ◽  
Millimeter Wave Source ◽  
Traveling Wave Tubes

In this chapter, brief outline is presented about gyro-devices. Gyro-devices comprise of a family of microwave devices and gyrotron is one among those. Various gyro devices, namely, gyrotron, gyro-klystron and gyro traveling-wave tubes (gyro-TWT) are discussed. Gyrotron is the only microwave source which can generate megawatt range of power at millimeter-wave and sub-millimeter-wave frequency. Gyrotron is the most suitable millimeter wave source for the heating of plasma in the Tokamak for the controlled thermoneuclear fusion reactors. This device is used both for the electron cyclotron resonance heating (ECRH) as well as for the electron cyclotron current drive (ECCD). In this chapter, the basic theory of gyrotron operation are presented with the explanation of various sub-systems of gyrotron. The applications of gyrotrons are also discussed. Also, the present state-of-the-art worldwide scenario of gyrotrons suitable for plasma heating applications are presented in details.

Electron Cyclotron Resonance Heating of Plasma in the Gas Dynamic Trap

2014 ◽  
Vol 9 (2) ◽  
pp. 13-21
Author(s):  
Aleksandr Solomakhin ◽  
Petr Bagryansky ◽  
Yuriy Kovalenko ◽  
Valeriy Savkin ◽  
Dmitriy Yakovlev
Keyword(s):  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Plasma Heating ◽  
Electron Cyclotron ◽  
Electron Cyclotron Resonance Heating ◽  
Total Power ◽  
Plasma Parameters ◽  
Experimental Conditions ◽  
Microwave Beam ◽  
Gas Dynamic

Electron cyclotron resonance plasma heating (ECRH) system has been recently installed on the gas dynamic trap (GDT) magnetic mirror. Two microwave beams are injected into the plasma at an angle of 36° with respect to the machine axis in a form of extraordinary (X) waves which are subsequently absorbed in the first harmonic cyclotron resonance. Each microwave beam is generated by a Buran-A type 450 kW/54.5 GHz gyrotron. The article reports on the first microwave injection experiments with limited total power of 300 kW. Adjustment of experimental conditions and magnetic field reconfiguration resulted in an increased diamagnetic signal, electron temperature and other plasma parameters

Adiabatic theory of nonlinear electron-cyclotron resonance heating

1991 ◽  
Vol 45 (1) ◽  
pp. 19-27 ◽  
Author(s):  
I. A. Kotel'nikov ◽  
G. V. Stupakov
Keyword(s):  
Electron Cyclotron Resonance ◽  
Plasma Heating ◽  
Hamiltonian Formalism ◽  
Energy Coupling ◽  
Electron Cyclotron ◽  
Electron Cyclotron Resonance Heating ◽  
Beam Power ◽  
Electron Trajectory ◽  
Ordinary Wave ◽  
Electron Gyrofrequency

Plasma heating at the electron-cyclotron frequency by an ordinary wave propagating at right-angles to a unidirectional magnetic field is considered. The injected microwave power is assumed to be sufficiently large that the relativistic change in electron gyrofrequency during one flight through the wave beam is much greater than inverse time of flight. The electron motion in the wave field is described using the Hamiltonian formalism in the adiabatic approximation. It is shown that energy coupling from the wave to electrons is due to a bifurcation of the electron trajectory, which results in a jump in the adiabatic invariant. The probability of a bifurcational transition from one trajectory to another is calculated analytically and used for the estimation of the beam power absorbed in the plasma.

scholarly journals Plans for the electron cyclotron heating system on J-TEXT

2019 ◽  
Vol 203 ◽  
pp. 04017 ◽  
Author(s):  
D. H. Xia ◽  
C. H. Liu ◽  
Y. K. Jin ◽  
H. Y. Ma ◽  
Y. Z. Tian ◽  
...  
Keyword(s):  
Electron Cyclotron Resonance ◽  
Heating System ◽  
Transmission Efficiency ◽  
Electron Cyclotron ◽  
Electron Cyclotron Resonance Heating ◽  
Electron Cyclotron Heating ◽  
Microwave Source ◽  
Injection Angle ◽  
Corrugated Waveguides ◽  
Flat Mirror

A new 105 GHz/500 kW/1 s electron cyclotron resonance heating (ECRH) system has been designed and being constructed on J-TEXT Tokamak. This system mainly consists of a microwave source, a transmission line, a launcher and other auxiliary units. Based on corrugated waveguides, the wave from the gyrotron can be efficiently transmitted with HE11 mode to the steerable quasi-optical launcher for injection. The transmission efficiency is about 85%, and the injection angle of the wave can be adjusted by the flat mirror of the launcher. Commissioning of this electron cyclotron heating system is scheduled to be done at 2019.

scholarly journals Plasma Heating of Tokamak by Microwaves at Electron Cyclotron Resonance Heating (ECRH)

2008 ◽  
Vol 5 (2) ◽  
pp. 217-223
Author(s):  
Baghdad Science Journal
Keyword(s):  
Numerical Simulation ◽  
United Kingdom ◽  
Cyclotron Resonance ◽  
Electromagnetic Waves ◽  
Electron Cyclotron Resonance ◽  
Plasma Heating ◽  
Electron Cyclotron ◽  
Electron Cyclotron Resonance Heating ◽  
Simulation Results ◽  
Full Absorption

The brief description to the theory of propagation of electromagnetic waves in plasma was done. The cutoff and resonance regions have been showed. The principles of plasma heating at electron cyclotron resonance (ECRH) method have been mentioned. The numerical simulation to three different station: Tosca station in United Kingdom, ISX-B station in USA and T-10 station in Russia had been done. The optical depth and the friction of energy absorbed A have been calculated. The simulation results indicate that both and A are increase with size of the tokamak and it is possible to obtain full absorption in large tokamak.

scholarly journals ECCD operations in the second experimental campaign at W7-X

2019 ◽  
Vol 203 ◽  
pp. 02013 ◽  
Author(s):  
M. Zanini ◽  
H.P. Laqua ◽  
T. Stange ◽  
C. Brandt ◽  
M. Hirsch ◽  
...  
Keyword(s):  
Current Density ◽  
Electron Cyclotron Resonance ◽  
Heating System ◽  
Electron Cyclotron ◽  
Current Drive ◽  
Electron Cyclotron Resonance Heating ◽  
Power Deposition ◽  
Plasma Radius ◽  
Rotational Transform ◽  
Low Order

In the Wendelstein 7-X stellarator, up to 7MW of power are delivered to the plasma by an electron cyclotron resonance heating system consisting of ten 140 GHz gyrotrons [1]. Due to the flexible front steering mirror of each beam line, the power deposition can be varied over the whole plasma radius and is optionally combinable with additional current drive. This flexibility, together with small toroidal currents in the stellarator, makes W7-X a perfect testbed for electron cyclotron current drive (ECCD) experiments, which have been successfully accomplished during the first two experimental campaigns OP1.1 and OP1.2a. Long discharges (lasting up to 30s) have been performed in OP1.2a, thus allowing the study of the current drive time evolution and the possibility to compensate the bootstrap current. ECCD efficiency has been studied using different power deposition profiles combined with a variation of the injection angles in relation to the magnetic field. During ECCD experiments, saw-tooth-like oscillations have been observed. Depending on the driven current density, ECCD can significantly modify the rotational transform (iota) profile, which can locally reach low order rational, thus triggering plasma instabilities. Different current density profiles have been tested, in order to try to understand the main trigger parameter for the instabilities. In particular, effects caused by current density gradient have been investigated producing both co- and counter-current drive at different radial positions: the total current drive is negligible, but a strong current gradient arises by driving currents in opposite directions. In this work an overview of ECCD operations in OP1.2a is given and first results, comparing different diagnostics, are presented. An initial 1-D model, coupled with the ray tracer TRAVIS, is developed, in order to have an estimation of current diffusion times and the radial position where a low order rational crosses the disturbed iota profile.

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