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Investigations of After Cavity Interaction in Gyrotrons Including the Effect of Non-uniform Magnetic Field

Author : Roy Choudhury, Amitavo

Publisher : KIT Scientific Publishing

Page : 146 pages

File Size : 36,56 MB

Release : 2014-02-05

Category : Technology & Engineering

ISBN : 3731501295

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Book Description

Dynamic after-cavity interaction (ACI) in megawatt-class gyrotrons is investigated that could lead to lower output mode purity and increased level of internal stray radiation. The self-consistent KIT-IHM multi-mode-code SELFT has been modified to extend the simulation domain into the radius up-taper section of the gyrotron cavity where the probability of ACI exists. Studies on four different gyrotron configurations confirm that undesired interactions in the up-taper region can result in additional parasitic oscillations with relative power in the 1%-range.



Investigations of After Cavity Interaction in Gyrotrons Including the Effect of Non-uniform Magnetic Field

Author : Amitavo Roy Choudhury

Publisher :

Page : 142 pages

File Size : 26,60 MB

Release : 2020-10-09

Category : Technology & Engineering

ISBN : 9781013283819

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Book Description

Dynamic after-cavity interaction (ACI) in megawatt-class gyrotrons is investigated that could lead to lower output mode purity and increased level of internal stray radiation. The self-consistent KIT-IHM multi-mode-code SELFT has been modified to extend the simulation domain into the radius up-taper section of the gyrotron cavity where the probability of ACI exists. Studies on four different gyrotron configurations confirm that undesired interactions in the up-taper region can result in additional parasitic oscillations with relative power in the 1%-range. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors.





Systematic Study of Key Components for a Coaxial-Cavity Gyrotron for DEMO

Author : Franck, Joachim

Publisher : KIT Scientific Publishing

Page : 274 pages

File Size : 11,98 MB

Release : 2017-05-11

Category : Technology (General)

ISBN : 3731506521

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Book Description

The physical design of cavity and magnetron injection gun (MIG) for a realistic, DEMO-compatible, coaxial-cavity 238 GHz 2 MW CW fusion gyrotron is developed in this work, having auxiliary frequencies at 170 GHz and 204 GHz. Novel systematic approaches towards multi-frequency mode selection, magnet requirements, and MIG design are presented. Mode deterioration and voltage depression variation due to insert misalignment versus cavity wall and/or versus electron beam are studied.



Feasibility and Operational Limits for a 236 GHz Hollow-Cavity Gyrotron for DEMO

Author : Kalaria, Parth Chandulal

Publisher : KIT Scientific Publishing

Page : 270 pages

File Size : 39,81 MB

Release : 2017-11-08

Category : Technology (General)

ISBN : 373150717X

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Book Description

The DEMOnstration fusion power plant (DEMO) will be the first fusion reactor, which is intended to generate net electrical power. For successful operation of DEMO, high-power gyrotrons with operating frequencies up to 240 GHz are required for plasma heating and stabilization. In this work, a systematic feasibility study and tolerance analysis are performed for the conventional-type hollow-cavity DEMO gyrotrons. The various approaches are also suggested to identify its operational limits.



Pushing the KIT 2 MW Coaxial-Cavity Short-Pulse Gyrotron Towards a DEMO Relevant Design

Author : Ruess, Sebastian

Publisher : KIT Scientific Publishing

Page : 190 pages

File Size : 39,29 MB

Release : 2021-01-22

Category : Technology & Engineering

ISBN : 3731510243

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Book Description

Magnetic fusion is one approach to generate thermonuclear fusion power in an environmental friendly way. The Electron Cyclotron Resonance Heating is considered as the major concept for startup, heating and control of the fusion plasma. Megawatt-class gyrotrons generate the required microwave power. This work focuses on advanced key components and technologies for a DEMO relevant 2 MW gyrotron. One major focus is on the development of advanced Magnetron Injection Guns. Another focus is on the red



Design and Experimental Investigation of a Second Harmonic 20 kW Class 28 GHz Gyrotron for Evaluation of New Emitter Technologies

Author : Malygin, Anton

Publisher : KIT Scientific Publishing

Page : 162 pages

File Size : 26,82 MB

Release : 2016-12-16

Category : Technology (General)

ISBN : 3731505843

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Book Description

Gyrotrons are high-power mm-wave tubes. Here, the design, construction and experimental investigation of a 20 kW, 28 GHz gyrotron (2nd harmonic) are reported. This tube was designed to evaluate new emitters for future highly efficient and reliable fusion gyrotrons and for material processing applications. Following experimental results have been achieved in CW operation: 22.5 kW output power at 23.4 kV electron beam voltage and 2.23 A beam current with the world record efficiency of 43 %.



Automated Mode Recovery and Electronic Stability Control for Wendelstein 7-X Gyrotrons

Author : Wilde, Fabian

Publisher : KIT Scientific Publishing

Page : 272 pages

File Size : 44,56 MB

Release : 2024-08-07

Category :

ISBN : 3731511606

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Book Description

Magnetic confinement fusion relies on plasma heating and plasma control using gyrotron oscillators providing at megawatt power levels. The operational reliability decreases when operating at the performance limits due to increasing parasitic mode activity. This work demonstrates for the first time the automated, fast recovery of nominal gyrotron operation during a pulse by exploiting the hysteretic gyrotron behaviour after a mode switch being in use at the Wendelstein 7-X ECRH facility.



A First 2 MW-Class (136)/170/204 GHz Multi-Frequency Gyrotron Pre-Prototype for DEMO: Design, Construction and Key Components Verification

Author : Ruess, Tobias

Publisher : KIT Scientific Publishing

Page : 258 pages

File Size : 27,79 MB

Release : 2023-10-26

Category :

ISBN : 3731513099

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Book Description

Ein Gyrotron wird in magnetisch eingeschlossenen Plasmaexperimenten für Heizung, Stromtrieb, Plasmastabilisierung und Plasmadiagnostik verwendet. In dieser Arbeit wird der erste Entwurf und Bau eines Mehrfrequenz-/Mehrzweck Pre-Prototyp Gyrotrons in koaxialer Technologie vorgestellt, das bei (136)/170/204 GHz mit einer Ausgangsleistung von 2 MW arbeitet. Dies ist der erste Schritt zum Betrieb bei Frequenzen bis zu 240 GHz unter Verwendung der Koaxialhohlraum-Gyrotrontechnologie. - A gyrotron is used in magnetically confined plasma experiments for heating, current drive, plasma stabilization and plasma diagnostics. This work presents the first design and construction of a multi-frequency / multi-purpose coaxial-cavity pre-prototype gyrotron operating at (136)/170/204 GHz with an output power of 2 MW. It is the first step towards operating frequencies up to 240 GHz using the coaxial-cavity gyrotron technology.



Time-dependent spectrum analysis of high power gyrotrons

Author : Schlaich, Andreas

Publisher : KIT Scientific Publishing

Page : 316 pages

File Size : 46,87 MB

Release : 2015-08-06

Category : Technology (General)

ISBN : 3731503751

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Book Description

In this work, a novel measurement system for the analysis of the gyrotron RF output spectrum was developed. It enables unprecedented time dependent measurements within a large bandwidth, dynamic range and unambiguous RF indication in the entire D-Band (110-170 GHz). Special attention was given to the investigation of parasitic RF oscillations, and the analysis of the interplay of thermal cavity expansion and ionization-based space charge neutralization at the start of long RF pulses.