This paper presents a review of the experimental achievements related to the development of high-power gyrotron oscillators for long-pulse or CW operation and pulsed gyrotrons for many applications. In addition, this work gives a short overview on the present development status of frequency step-tunable and multi-frequency gyrotrons, coaxial-cavity multi-megawatt gyrotrons, gyrotrons for technological and spectroscopy applications, relativistic gyrotrons, large orbit gyrotrons (LOGs), quasi-optical gyrotrons, fast- and slow-wave cyclotron autoresonance masers (CARMs), gyroklystrons, gyro-TWT amplifiers, gyrotwystron amplifiers, gyro-BWOs, gyro-harmonic converters, gyro-peniotrons, magnicons, free electron masers (FEMs), and dielectric vacuum windows for such high-power mm-wave sources. Gyrotron oscillators (gyromonotrons) are mainly used as high-power millimeter wave sources for electron cyclotron resonance heating (ECRH), electron cyclotron current drive (ECCD), stability control, and diagnostics of magnetically confined plasmas for clean generation of energy by controlled thermonuclear fusion. The maximum pulse length of commercially available 140 GHz, megawatt-class gyrotrons employing synthetic diamond output windows is 30 min (CPI and European KIT-SPC-THALES collaboration). The world record parameters of the European tube are as follows: 0.92 MW output power at 30-min pulse duration, 97.5% Gaussian mode purity, and 44% efficiency, employing a single-stage depressed collector (SDC) for energy recovery. A maximum output power of 1.5 MW in 4.0-s pulses at 45% efficiency was generated with the QST-TOSHIBA (now CANON) 110-GHz gyrotron. The Japan 170-GHz ITER gyrotron achieved 1 MW, 800 s at 55% efficiency and holds the energy world record of 2.88 GJ (0.8 MW, 60 min) and the efficiency record of 57% for tubes with an output power of more than 0.5 MW. The Russian 170-GHz ITER gyrotron obtained 0.99 (1.2) MW with a pulse duration of 1000 (100) s and 53% efficiency. The prototype tube of the European 2-MW, 170-GHz coaxial-cavity gyrotron achieved in short pulses the record power of 2.2 MW at 48% efficiency and 96% Gaussian mode purity. Gyrotrons with pulsed magnet for various short-pulse applications deliver P out  = 210 kW with τ  = 20 μs at frequencies up to 670 GHz ( η  ≅ 20%), P out  = 5.3 kW at 1 THz ( η  = 6.1%), and P out  = 0.5 kW at 1.3 THz ( η  = 0.6%). Gyrotron oscillators have also been successfully used in materials processing. Such technological applications require tubes with the following parameters: f   >  24 GHz, P out  = 4–50 kW, CW, η   >  30%. The CW powers produced by gyroklystrons and FEMs are 10 kW (94 GHz) and 36 W (15 GHz), respectively. The IR FEL at the Thomas Jefferson National Accelerator Facility in the USA obtained a record average power of 14.2 kW at a wavelength of 1.6 μm. The THz FEL (NOVEL) at the Budker Institute of Nuclear Physics in Russia achieved a maximum average power of 0.5 kW at wavelengths 50–240 μm (6.00–1.25 THz).

/pdf/state-of-the-art-of-high-power-gyro-devices-and-free-3dd9d7und5.pdf

State-of-the-art of high power gyro-devices and free electron masers update 1995

This report gives an update of the worldwide experimental achievements in the development of long-pulse gyrotron oscillators for fusion plasma heating, plasma diagnostics and materials processing. In addition, this work gives a short overview of the present development status of coaxial-cavity multi-megawatt gyrotrons, gyrotrons for technological and spectroscopy applications, relativistic gyrotrons, quasi-optical gyrotrons, cyclotron autoresonance masers, gyro-amplifiers, gyro-BWO's, free electron masers and of vacuum windows for such high-power mm-wave sources.

/pdf/state-of-the-art-of-high-power-gyro-devices-and-free-1mmeiw5vph.pdf

State-of-the-Art of High Power Gyro-Devices and Free Electron Masers. Update 2011. (KIT Scientific Reports ; 7606)

Dieser Bericht geht auf den experimentellen Stand von Hochleistungs-Gyrotron-Rohren fur verschiedene Anwendungen ein. Auserdem wird uber frequenzdurchstimmbare Gyrotrons, Multi-MW-Gyrotrons mit koaxialem Resonator, Gyrotrons fur technologische und spektroskopische Anwendungen, relativistische Gyrotrons, Zyklotron-Autoresonanz-Maser, Gyroklystrons, Gyro-TWT-und Gyrotwystron-Verstarker, Gyro-RWO, Gyro-Harmonische-Konvertoren Gyro-Peniotrons, Magnicons, und Frei-Elektronen-Maser berichtet.

/pdf/state-of-the-art-of-high-power-gyro-devices-and-free-wis23tsqld.pdf

State-of-the-Art of High Power Gyro-Devices and Free Electron Masers. Update 2015 (KIT Scientific Reports ; 7717)

At high-power operation points, in the improved W7-X SN4R series gyrotron spurious parasitic oscillations could be detected experimentally. This paper describes high-dynamic RF spectrum measurements in short and long pulse operation and corresponding simulations with a self-consistent gyrotron interaction code. Preliminary simulation results show good agreement with the measured spectra and suggest that the frequencies observed originate from so-called after-cavity interactions (ACI) in the uptaper/launcher region of the tube.

Examination of parasitic after-cavity oscillations in the W7-X series gyrotron SN4R

A systematic theoretical and experimental study on 94-GHz second-harmonic gyrotron with a superconducting magnet system is presented in this paper. A complex cavity with gradual transition is employed in the gyrotron. A self-consistent field nonlinear theory is used and numerical simulation results for electron beam interaction with TE02–TE03 modes are given. A pulse output power of 235.2 kW is obtained by simulation at a beam voltage of 60 kV with beam current of 10 A and magnetic field 17 kG, corresponding to an efficiency of 39.2 %.

Design and Experimental Demonstration of a 94-GHz Gyrotron with Complex Cavity Operating at the Second Harmonic

Recent progress on the 1 MW, 140 GHz, CW series gyrotrons for W7-X.

European Development of a Gyrotron for ITER: Design and Analysis, and Support to the Industrial Contracts

Abs tract: Electron cyclotron heating (ECH) has proven to be one of the most attractive heating schemes for stellarators, as it provides net current free plasma start up and heating. Both, the stellarator Wendelstein 7-X (W7-X), which is under construction at IPP-Greifswald, Germany, and the ITER tokamak, which will be built at Cadarache, France, will be equipped with a strong EC-heating and current drive system. Both systems are comparable in frequency and have CW (continuous wave) capability (0.14 THz, 10 MW for W7-X and 0.17 THz, 24 MW for ITER). The commissioning of the ECH plant for W7-X is well underway, the status of the project and first integrated full power test results from two modules are reported and may provide valuable input for the ITER plant. The 10 gyrotrons at W7-X will be arranged in two sub-groups symmetrically to a central beam duct in the ECH hall. The RF-wave of each subgroup will be combined and transmitted by a purely optical multibeam wave guide transmission line (copper mirrors) from the gyrotrons to the plasma torus. The combination of the 5 gyrotron beams to two beam lines each with a power of 5 MW reduces the complexity of the system considerably. The single-beam as well as the multi-beam waveguide mirrors and the polarizers have been already manufactured. Cold tests of a full size uncooled prototype line delivered an efficiency exceeding 90%. The mm-wave power will be launched to the plasma through ten synthetic-diamond barrier windows and in-vessel quasi-optical plug-in launchers allowing each 1 MW RF-beam to be steered independently. The polarization as well as the poloidal and toroidal launch angle will be adjusted individually to provide optimum conditions for different heating and current drive scenarios. The first series gyrotrons were tested and yielded a total output power of 0.98 MW, with an efficiency of 31% (without a single-stage depressed collector) in short-pulse operation and of 0.92 MW in pulses of 1800 s (efficiency of almost 45% at a depression voltage of 29 kV). The Gaussian mode output power was 0.90 MW and the power measured in a calorimetric load after a 25-m-long quasi-optical transmission line (seven mirrors) was 0.87 MW.

/pdf/10-mw-0-14-thz-cw-gyrotron-and-optical-transmission-system-4dtfh88wxd.pdf

10 MW , 0.14 THz, CW Gyrotron and Optical Transmission System for Millimeter Wave Heating of Plasmas in the Stellarator W7-X

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

W. Leonhardt

Author Tools

Chat about Author

Papers

Recent progress on the 1 MW, 140 GHz, CW series gyrotrons for W7-X.

European Development of a Gyrotron for ITER: Design and Analysis, and Support to the Industrial Contracts

10 MW , 0.14 THz, CW Gyrotron and Optical Transmission System for Millimeter Wave Heating of Plasmas in the Stellarator W7-X