scholarly journals Theoretical Study on the Operation of the EU/KIT TE34,19-Mode Coaxial-Cavity Gyrotron at 170/204/238 GHz

2019 ◽  
Vol 203 ◽  
pp. 04014 ◽  
Author(s):  
Tobias Ruess ◽  
Konstantinos Avramidis ◽  
Gerd Gantenbein ◽  
Stefan Illy ◽  
Zisis Ioannidis ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Short Pulse ◽  
Test Facility ◽  
Coaxial Cavity ◽  
Microwave Beam ◽  
Mode Content ◽  
Theoretical Investigations ◽  
Gaussian Mode ◽  
Multiple Frequencies ◽  
The Eu

The 170 GHz 2 MW TE34,19-mode coaxial-cavity modular short-pulse pre-prototype gyrotron at KIT was recently modified in order to verify the multi-megawatt coaxial-cavity technology at longer pulses. In parallel, theoretical investigations on a possibility to operate the 170 GHz TE34,19-mode coaxial-cavity prototype at multiple frequencies up to 238 GHz have been started, with a goal to find a configuration at which the tube could operate in the KIT FULGOR gyrotron test facility using the new 10.5 T SC magnet. This paper indicates which adjustments have to be made and show the feasibility of the multi-frequency operation. Small modifications at the gyrotron cavity will support an RF output power of more than 2 MW at 170/204 GHz. Furthermore, a new gyrotron launcher has been designed capable of producing a Gaussian microwave beam with a Gaussian mode content of more than 96% at these frequencies.

RF Behavior and Launcher Design for a Fast Frequency Step-tunable 236 GHz Gyrotron for DEMO

Frequenz ◽  
2017 ◽  
Vol 71 (3-4) ◽  
Author(s):  
P. C. Kalaria ◽  
K. A. Avramidis ◽  
J. Franck ◽  
G. Gantenbein ◽  
S. Illy ◽  
...  
Keyword(s):  
Mode Selection ◽  
Step Frequency ◽  
Coaxial Cavity ◽  
Operating Modes ◽  
Mode Content ◽  
Frequency Tunability ◽  
Gaussian Mode ◽  
Cavity Design ◽  
Frequency Tunable ◽  
Tunable Gyrotron

AbstractAs part of the EUROfusion project, the conceptual design of a 1 MW 236 GHz hollow-cavity gyrotron is ongoing at IHM, KIT for a DEMOnstration Power Plant (DEMO), along with a 2 MW coaxial-cavity design concept. Fast frequency-tunable gyrotrons (tuning within a few seconds) are recommended for plasma stabilization using a non-steerable antenna. In this work, the mode-selection approach for such a frequency-tunable gyrotron is presented and suitable operating modes for fast frequency tunability are suggested. Magnetic field tuning has been studied as an effective technique to tune the gyrotron operating frequency. The step-tunability of the 236 GHz gyrotron within the frequency range of ±10 GHz in steps of 2–3 GHz is demonstrated in numerical simulations. A hybrid-type Quasi-Optical Launcher (QOL) has been designed for a step-frequency tunable gyrotron with sufficiently high Fundamental Gaussian Mode Content (FGMC).

scholarly journals Metrology techniques for the verification of the alignment of the EU gyrotron prototype for ITER

2019 ◽  
Vol 203 ◽  
pp. 04015
Author(s):  
Francisco Sanchez ◽  
Ferran Albajar ◽  
Alessandro Lo Bue ◽  
Stephano Alberti ◽  
Konstantinos Avramidis ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Pulse Duration ◽  
Short Pulse ◽  
Superconducting Magnet ◽  
Heating System ◽  
Test Facility ◽  
Magnetic Field Axis ◽  
Full Power ◽  
The Magnetic Field ◽  
The Eu

The EU gyrotron for the ITER Electron Cyclotron (EC) heating system has been developed in coordinated efforts of the EGYC Consortium, Thales ED (TED) and Fusion for Energy (F4E) and under the supervision of ITER Organization Central Team. After the successful verification of the design of the 1MW, 170 GHz hollow cylindrical cavity gyrotron operating at the nominal TE32,9 mode with a short pulse gyrotron prototype at KIT, an industrial CW gyrotron prototype was manufactured by TED and tested at ~0.8 MW output power and 180 s pulse duration, which is the limit of the HV power supply currently available at KIT. The experiments are being continued at SPC in 2018 to extend further the pulse duration, taking advantage of the existing CW full-power capabilities of the gyrotron test facility recently upgraded for the FALCON project. The gyrotron cavity interaction is very sensitive to the alignment of the internal mechanical parts of the gyrotron tube with the magnetic field generated by the superconducting magnet within a typical range of 0.2 – 0.5 mm. The control of the tolerances and deformations becomes therefore critical to achieving the target performances. With the EU gyrotron prototype it was possible to adjust the alignment of the gyrotron tube with respect to the magnetic field axis during the installation and commissioning phase. The actual shift and tilt movements were verified using advanced metrology methods such as photogrammetry. In this paper, the alignment control techniques and procedures will be discussed also in view of enhancing the reproducibility of gyrotron performance during series production.

scholarly journals Report of recent experiments with the European 1 MW, 170 GHz CW and SP prototype gyrotrons for ITER

2019 ◽  
Vol 203 ◽  
pp. 04006 ◽  
Author(s):  
Zisis Ioannidis ◽  
Tomasz Rzesnicki ◽  
Ferran Albajar ◽  
Stefano Alberti ◽  
Konstantinos Avramidis ◽  
...  
Keyword(s):  
Short Pulse ◽  
Maximum Efficiency ◽  
Total Efficiency ◽  
Rf Power ◽  
High Voltage Power Supply ◽  
Short Pulses ◽  
Mode Content ◽  
Gaussian Mode ◽  
Depressed Collector ◽  
Interaction Efficiency

The European 1 MW, 170 GHz industrial CW prototype gyrotron has been designed within EGYC (European GYrotron Consortium) in collaboration with the industrial partner Thales Electron Devices (TED) and under the coordination of Fusion for Energy (F4E). This is a conventional (hollow) cavity gyrotron that is based on the 1 MW, 170 GHz short-pulse (SP) modular gyrotron, which has been designed and manufactured by KIT in collaboration with TED. The SP prototype has been tested in multiple experimental campaigns since 2015 and the nominal cavity mode TE32,9 is exited at 170.1 GHz, producing RF power above 1 MW with 35 % interaction efficiency. The first phase of the experiments with the CW industrial gyrotron was successfully completed at KIT in 2016, verifying most of the ITER specifications. Short pulses (<10ms) deliver RF power higher than 0.9 MW with a total efficiency of 26 % (in non-depressed collector operation). The Gaussian mode content of the RF beam is 97 %. Pulses with duration of 180 s (limited by the high-voltage power supply at KIT) produce power more than 0.8 MW with maximum efficiency 38 % (in depressed collector operation). In this work the achievements with the SP and the CW prototype gyrotrons are summarized.

scholarly journals Improved Simulation of Quasi-Optical Launchers for High Power Gyrotrons with Smoothing Algorithm

2019 ◽  
Vol 203 ◽  
pp. 04008
Author(s):  
Jianbo Jin ◽  
Gerd Gantenbein ◽  
Tomasz Rzesnicki ◽  
Manfred Thumm ◽  
John Jelonnek
Keyword(s):  
High Power ◽  
Smoothing Algorithm ◽  
Coaxial Cavity ◽  
Mode Content ◽  
Fabrication Errors ◽  
Optical Output ◽  
Stray Radiation ◽  
Mode 2 ◽  
Gaussian Mode ◽  
Wall Profile

Numerically optimized launchers for the quasi-optical output coupler of high power gyrotrons have been developed to provide RF beams with high Gaussian mode content. Generally, the profiles of numerically optimized launchers are quite complicated, so the improvement of their tolerance to fabrication errors is very important. In order to reduce the stray radiation generated by launchers with quite complicated wall profile, and also to reduce their sensitivity to fabrication errors, a method for the smoothing of the numerically optimized launcher wall has been developed at KIT, which is based on the spectrum reconstruction approach. As an example, a launcher designed for the KIT TE34,19-mode, 2 MW CW coaxial-cavity gyrotron has been investigated.

A theoretical study on photophysical properties of triphenylamine-cored molecules with naphthalimide arms and different π-conjugated bridges as organic solar cell materials

2015 ◽  
Vol 17 (3) ◽  
pp. 2094-2103 ◽  
Author(s):  
R. F. Jin ◽  
Y. F. Chang
Keyword(s):  
Charge Transfer ◽  
Solar Cell ◽  
Organic Solar Cell ◽  
Theoretical Study ◽  
Photophysical Properties ◽  
Theoretical Investigations

Theoretical investigations show that star-shaped molecules are expected to be promising candidates for charge transfer and donor materials for OSCs.

Enhanced operation of the Eu Ec test facility

2019 ◽  
Vol 146 ◽  
pp. 1942-1946 ◽  
Author(s):  
D. Fasel ◽  
S. Alberti ◽  
J. Dubray ◽  
T. Goodman ◽  
J.-P. Hogge ◽  
...  
Keyword(s):  
Test Facility ◽  
The Eu

Demonstration of thin film compression for short-pulse X-ray generation

2019 ◽  
Vol 34 (34) ◽  
pp. 1943015
Author(s):  
D. M. Farinella ◽  
M. Stanfield ◽  
N. Beier ◽  
T. Nguyen ◽  
S. Hakimi ◽  
...  
Keyword(s):  
Thin Film ◽  
Imaging System ◽  
Short Pulse ◽  
Laser Pulses ◽  
Single Cycle ◽  
X Ray ◽  
Ultrafast Laser Pulses ◽  
Solid Density ◽  
Fs Laser ◽  
Gaussian Mode

Thin film compression to the single-cycle regime combined with relativistic compression offers a method to transform conventional ultrafast laser pulses into attosecond X-ray laser pulses. These attosecond X-ray laser pulses are required to drive wakefields in solid density materials which can provide acceleration gradients of up to TeV/cm. Here we demonstrate a nearly 99% energy efficient compression of a 6.63 mJ, 39 fs laser pulse with a Gaussian mode to 20 fs in a single stage. Further, it is shown that as a result of Kerr-lensing, the focal spot of the system is slightly shifted on-axis and can be recovered by translating the imaging system to the new focal plane. This implies that with the help of wave-front shaping optics the focusability of laser pulses compressed in this way can be partially preserved.

scholarly journals KIT coaxial gyrotron development: from ITER toward DEMO

2018 ◽  
Vol 10 (5-6) ◽  
pp. 547-555 ◽  
Author(s):  
S. Ruess ◽  
K. A. Avramidis ◽  
M. Fuchs ◽  
G. Gantenbein ◽  
Z. Ioannidis ◽  
...  
Keyword(s):  
Output Power ◽  
Electron Cyclotron Resonance ◽  
Short Pulse ◽  
Electron Cyclotron Resonance Heating ◽  
Major Step ◽  
Coaxial Cavity ◽  
Design And Manufacturing ◽  
Institute Of Technology ◽  
Coaxial Gyrotron ◽  
Karlsruhe Institute

Karlsruhe Institute of Technology (KIT) is doing research and development in the field of megawatt-class radio frequency (RF) sources (gyrotrons) for the Electron Cyclotron Resonance Heating (ECRH) systems of the International Thermonuclear Experimental Reactor (ITER) and the DEMOnstration Fusion Power Plant that will follow ITER. In the focus is the development and verification of the European coaxial-cavity gyrotron technology which shall lead to gyrotrons operating at an RF output power significantly larger than 1 MW CW and at an operating frequency above 200 GHz. A major step into that direction is the final verification of the European 170 GHz 2 MW coaxial-cavity pre-prototype at longer pulses up to 1 s. It bases on the upgrade of an already existing highly modular short-pulse (ms-range) pre-prototype. That pre-prototype has shown a world record output power of 2.2 MW already. This paper summarizes briefly the already achieved experimental results using the short-pulse pre-prototype and discusses in detail the design and manufacturing process of the upgrade of the pre-prototype toward longer pulses up to 1 s.

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