Development of the Q-band ECE imaging system in the large helical device

2022 ◽  
Vol 17 (01) ◽  
pp. C01016
Author(s):  
Y. Goto ◽  
T. Tokuzawa ◽  
D. Kuwahara ◽  
K. Ichinose ◽  
H. Tsuchiya ◽  
...  

Abstract In this study, we developed the Electron Cyclotron Emission Imaging (ECEI) system with the Q-band in the Large Helical Device (LHD). ECEI measurement makes it possible to obtain the spatiotemporal structure of magnetohydrodynamics (MHD) instabilities in the high-β plasma. Although there were several difficulties for realizing the multi-channelization, such as local oscillator (LO) optics and an expensive high-power LO source, we have solved these problems by developing a Local Integrated Antenna array (LIA) which has an internal LO supply, using a frequency doubler integrated circuit on each channel, instead of a conventional Horn-antenna Mixer Array (HMA) with common LOs. In addition, we have made some improvements to enhance the quality of the measurement signal. First, we developed and introduced notch filters that prevent the strong Electron Cyclotron Resonance Heating (ECRH) stray signal from being mixed into the measurement circuit. Second, the position of the doubler built in the printed circuit board was reconsidered to prevent the mixing of higher harmonic components into the mixer. Also, we have adopted the Logarithmic detector (LOG detector) to deal with the wide dynamic range of the plasma fluctuation. After these improvements, for the first time, we could successfully obtain the initial results of the two-dimensional temperature distribution and its fluctuation distribution in the LHD.

Author(s):  
William Ng ◽  
Kevin Weaver ◽  
Zachary Gemmill ◽  
Herve Deslandes ◽  
Rudolf Schlangen

Abstract This paper demonstrates the use of a real time lock-in thermography (LIT) system to non-destructively characterize thermal events prior to the failing of an integrated circuit (IC) device. A case study using a packaged IC mounted on printed circuit board (PCB) is presented. The result validated the failing model by observing the thermal signature on the package. Subsequent analysis from the backside of the IC identified a hot spot in internal circuitry sensitive to varying value of external discrete component (inductor) on PCB.


2005 ◽  
Vol 47 (2) ◽  
pp. 108-118 ◽  
Author(s):  
E. Westerhof ◽  
J. A. Hoekzema ◽  
G. M. D. Hogeweij ◽  
R. J. E. Jaspers ◽  
F. C. Schüller ◽  
...  

2014 ◽  
Vol 9 (2) ◽  
pp. 13-21
Author(s):  
Aleksandr Solomakhin ◽  
Petr Bagryansky ◽  
Yuriy Kovalenko ◽  
Valeriy Savkin ◽  
Dmitriy Yakovlev

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


Circuit World ◽  
2020 ◽  
Vol 46 (3) ◽  
pp. 215-219
Author(s):  
Akhendra Kumar Padavala ◽  
Narayana Kiran Akondi ◽  
Bheema Rao Nistala

Purpose This paper aims to present an efficient method to improve quality factor of printed fractal inductors based on electromagnetic band-gap (EBG) surface. Design/methodology/approach Hilbert fractal inductor is designed and simulated using high-frequency structural simulator. To improve the quality factor, an EBG surface underneath the inductor is incorporated without any degradation in inductance value. Findings The proposed inductor and Q factor are measured based on well-known three-dimensional simulator, and the results are compared experimentally. Practical implications The proposed method was able to significantly decrease the noise with increase in the speed of radio frequency and sensor-integrated circuit design. Originality/value Fractal inductor is designed and simulated with and without EBG surfaces. The measurement of printed circuit board prototypes demonstrates that the inclusion of split-ring array as EBG surface increases the quality factor by 90 per cent over standard fractal inductor of the same dimensions with a small degradation in inductance value and is capable of operating up to 2.4 GHz frequency range.


1991 ◽  
Vol 45 (1) ◽  
pp. 19-27 ◽  
Author(s):  
I. A. Kotel'nikov ◽  
G. V. Stupakov

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.


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