NEWS LETTE R
of the International Consortium“Development of High-Power Terahertz
Science & Technology”
February 2018

№8

CONTENT Editorial(Page 1)

How to contribute to the Newsletter
 Extending the international collaboration
New schemes and frameworks for a collaborative research at FIR UF Center Short paper
N. Ginzburg, et al., “Terahertz-Range Planar Gyrotrons with Transverse Energy Extraction
Operating at the Fundamental and High-Order Cyclotron Harmonics
 Next IRMMW-THz Conference in Nagoya, Japan Other upcoming conferences
 List of selected recent publications and patents
 New books
 News from the Net(Page 2)
(Page 3)

(Page 7)
(Page 9)(Page 10)
(Page 17)
(Page 18)

EDITORIAL: HOW TO CONTRIBUTE TO THE NEWSLETTER
Dear Reader,
We are inviting contributions to the following rubrics:• Research highlights (annotations) presenting the projects pursued by the members of the Consortium.
• Short regular papers.
• Proposals for collaborative research work.
• News from the participating institutions.
• Information about conferences, symposia, workshops, seminars.
• Programs and frameworks for an exchange of visits and mobility of researchers. Job opportunities(especially for young researchers, e.g. postdoctoral positions, specializations, internships).
• Annotations of books, conference proceedings, software and internet resources. Additions to the list of
the recent scientific publications and conference reports at the website of the Consortium(http://fir.ufukui.ac.jp/Website_Consortium/publist.html ).
• Information and announcements about awards and nominations.
• Short presentations of laboratories and research groups belonging to the participating institutions.
Please submit your contributions to the Newsletter as well as requests for information to:Professor Toshitaka Idehara
Supervisor of International Cooperation
and Facilitator of the International
Consortium
FIR UFidehara@fir.u-fukui.ac.jp

Dr. Svilen Sabchevski
Editor of the website and the Newsletter
Institute of Electronics of the Bulgarian
Academy of Sciences
IE-BASsabch@ie.bas.bg

EXTENDING THE INTERNATIONAL COLLADORATIONOver the years, FIR UF Research Center has always been an active promoter of a broad international
collaboration with many institutions around the world using various frameworks and schemes based on the signed
agreements for academic exchange and memorandums of understanding. On this basis, many researchers fromoverseas were invited as visiting research fellows for various terms (typically 2-3 months) or for short visits(usually a couple of weeks) for collaborative research. As an organizer and a facilitator of the International
Consortium for Development of High-Power Terahertz Science and Technology (established in 2015), FIR UF
continues to seek new efficient forms for co-operation between the participating members (13 institutions from
9 countries altogether). From the beginning of the current academic year (which in Japan begins on 1 st of April)FIR UF started successfully the implementation of a new scheme based on the cross-appointment of the overseas
researchers. The first cross-appointed professors were Irina Zotova (accompanied by the PhD student Andrei
Fokin, whose supervisor she is), Andrei Savilov, from the Institute of Applied Physics of the Russian Academyof Sciences (IAP-RAS) and Svilen Sabchevski from the Institute of Electronics of the Bulgarian Academy of
Sciences (IE-BAS). Dr. Tsun-Hsu Chang from the National Tsing Hua University in Taiwan, Vladimir Manuilov
from the Nizhny Novgorod State University, and Naum Ginzburg from IAP-RAS joined the academic staff of
FIR UF as visiting professors. During his short visit in August 2018, Professor Mikhail Glyavin presented thescientific program of the cross-appointed researchers from IAP-RAS at the seminar of FIR UF.
Both the cross-appointed and the visiting researchers work at the International Research Division which was
founded at FIR UF Center in the FY 2016. Together with their Japanese colleagues of the host institution they
are conducting studies on the development of high-performance sub-terahertz and terahertz gyrotons for a wide
range of applications in the high-power terahertz science and technology.
A nice example of a successful research carried out in the framework of this collaboration is the development
and experimental investigation of a novel double-beam gyrotron, which operates at the second harmonic of thecyclotron frequency. Such tube with an output frequency of about 0.8 THz is an appropriate radiation source forthe next generation of a high-field DNP-NMR spectroscopy at 1.2 GHz. Another variety of such tube with twogenerating beams is an oscillator with one generating beam and one absorbing beam which suppress the excitationof the competing parasitic mode. A realization of the latter scheme is under investigation now. Several other very
attractive and promising concepts of advanced gyrotrons are under consideration as well. Among them is theplanar gyrotron with a transverse (with respect to the propagation direction of the sheet electron beam) extractionof the radiation (see the short paper in the current issue of the Newsletter). Other direction towards a highharmonic operation and thus towards higher frequencies is the concept of the large orbit gyrotron (LOG), which
utilizes axis-encircling (uniaxial) helical electron beam. The experience at FIR UF in the development of the first
LOG with a permanent magnet is considered as a basis for the realization of various other new and promising
LOGs (e.g. with sectioned cavities).
We expect that such an active collaboration will enrich further the research conducted at FIR UF and willcontribute significantly to the realization of the goals of the International Consortium.
In October 2017, the Research Center for Development of Far-Infrared Region, University of Fukui (FIR UF),announced a new International Collaborative Research Program. This program aims to support the developmentof the high-power Terahertz science and technology through international personnel exchange visits and studies,
being performed at the FIR UF in a wide interdisciplinary field that includes the development of radiation sources(most notably gyrotrons and other gyro-devices) and their applications in physical experiments and advanced
novel technologies.
More detailed information about the International Collaborative Research Program and the application form
are available at the website of the International Consortium for Development of High-Power Terahertz Scienceand Technology (visit: http://fir.u-fukui.ac.jp/Website_Consortium/index.html). We are inviting proposals forcollaborative research work advancing to this new International Collaborative Research Program.

SHORT PAPER
Terahertz-Range Planar Gyrotrons with Transverse Energy Extraction Operating at theFundamental and High-Order Cyclotron Harmonics
1,2

N.S. Ginzburg, 1T. Idehara, 2V.Yu. Zaslavsky, 2I.V. Zheleznov, 2A.M. Malkin, 1,2I.V. Zotova,
2
A.S. Sergeev, and 1,2M.Yu. Glyavin
1

Research Center for Development of Far-Infrared Region,
University of Fukui (FIR UF),2
Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS)
Introduction
In the last few years, a considerable progress has been achieved in the development of terahertz-range gyrotrons[1-4]. At the frequency of 1 THz, the radiation power amounts several kilowatts in conventional gyrotrons withtubular helical beams formed by magnetron injection guns [1-3] and up to hundreds of watts in large-orbit
gyrotrons (LOG) with axis-encircling electron beams [4]. All these experiments were performed in the pulse
regime. Recently, terahertz-range radiation at the second cyclotron harmonic was achieved. In the latter
experiment, a superconductive magnet was used. A typical feature of such magnets is a fairly large diameter ofthe warm bore of 5-10 cm. At the same time, the transverse cross-sections of conventional terahertz gyrotrons
with cylindrical resonator are quite limited and amounts of several millimeters (Fig.1a). These strong limitations
are caused by problems with mode selection that restricted admissible waveguide radius. As a result, restrictions
on the driving beam current arise. In order to provide adequate starting conditions, one should increase theinteraction length above an optimal value that together with rather small cross-section results in substantial Ohmic
losses. According to the simulations for experimental conditions corresponding to [5], the Ohmic losses amountto 80% of the radiation power. Obviously, the improvement of mode selection is the key issue in the further
development of short-wavelength gyrotrons.

Fig.1. Transverse cross-section of (a) a double-beam and(b) a planar gyrotrons in the scale of the warm bore of theJMTD15T52 cryo-magnet.

Fig.2. The model of a planar gyrotron. Arrows
show the directions of energy extraction.

For a drastic increase in the output power of short-wavelength gyrotrons, we suggest using a planar schemewith a sheet electron beam and transverse (with respect to the electrons translation velocity) electromagnetic
energy extraction (Fig.2). The main advantage of this scheme comparing it to the conventional cylindricalgeometry is the possibility of effective mode selection over the open transverse coordinate in a combination withradiation out-coupling, which leads to a substantial reduction of the Ohmic losses [6,7]. It is important to notethat in the existing cryomagnets, the warm bore diameter is sufficient for a significant increase of the cross-section of the terahertz-range gyrotrons and provides enough space for installation of additional reflectors
required for arrangement of transmission of generated radiation in the direction of the collector.
It should be noted that in the considered planar scheme there are some peculiarities related to the excitationof odd ( s  1,3...) and even ( s  2,4...) cyclotron harmonics, respectively. Under the assumption that the sheet
electron beam is injected along the resonator axis (in the middle of the cavity between the plates), the interactionof an electron beam at odd cyclotron harmonics occurs only for the resonator modes with odd transverse indexesn  1,3..., while the interaction at even harmonics occurs only for the modes with even transverse indexes n 
2,4... (see Fig.3). Moreover, for example, for operation at the second harmonic, it is beneficial to use an evenresonator mode with indexes n equal to a doubled even number. In this case interaction at second harmonic will
be not accompanied by a simultaneous excitation of a lower order mode at the first cyclotron harmonic since thecoupling factor of the 1st harmonic with an even mode is equal to zero. From the other hand, for excitation at the
odd cyclotron harmonic the number of the resonator mode should not be dividable by s . For example, for s  3, the resonator mode number may be n  5, 7,11... . In this case the parasitic mode at the 2nd cyclotron harmonic
is not excited.

Odd (symmetric) modez

Odd cyclotron
harmonics
S=1,3,…

Even cyclotron
Harmonics
S=2,4,…

Gs  y 

Ex

Even (antisymmetric)mode

Gs  y z

Odd cyclotron
harmonics
S=1,3,…

Even cyclotron
Harmonics
S=2,4,…

Gs  y ExGs  y 

y

y
e

e

y

y

y

y

Fig.3. The coupling factor G  y  for odd and even cyclotron harmonics.

Results of simulations
Simulations of the nonlinear dynamics of terahertz-range planar gyrotrons operating at the 1st and 2nd
cyclotron harmonics were performed based on the self-consistent time-domain model developed in [6]. Similar
to the well-known model of low-Q gyrotrons [8], the field evolution in [6] is described by a non-uniform parabolic
equation. However, in order to describe the transverse energy extraction the diffraction of radiation over thetransverse coordinate x is taken into account, while in z-direction the gyrotron resonator is closed by cut-off necks(see Fig.2). The main parameters are presented in Table 1.

Table 1
Harmonic number, sMode number
Wavelength, mm
Ib , A
U, kV
H0, T
g
lx, mmLy, mmlz, mmEfficiency , %Output power , kW
Losses, %

1
11
0.768
2
30
~15.03
1.2
15.3
4.22
10
31
16
15

2
12
0.384
2
30
~14.84
1.2
7.7
2.3
20
7
2.9
30

A) Operation at the first cyclotron harmonic
For the first harmonic operation, we choose the gap between plates of l y  4.22 mm (5.5  ), whichcorresponds to the eleventh (TE11) mode of a planar waveguide. The sheet beam width was chosen equal to thetransverse size of the interaction space of 15.3 mm (20  ). Simulations show the existence of zones of cyclotron
resonance mismatch  , for which a steady-state regime takes place with excitation of modes having a different
number of longitudinal variations m . The spatial distribution of radiated field amplitude for the mode with asingle longitudinal variation m  1 is shown in Fig.4a. The dependence of electron efficiency  , output power
Pout and Ohmic loss power Pohm on the beam current I b are presented in Fig.4b-d. For the fixed current wehave optimized the system with respect to the interaction length l z and the resonance mismatch  . One can seethat with increasing the current, the optimal length decreases together with the Ohmic losses. Thus, the total
radiation power increases. For a current of 20 A, the output power amounts to 115 kW at an electron efficiencyof 21%. The Ohmic losses don’t exceed 11%.

a

a

b

P, kW

Pout
Pohm

X

, %

Ibeam, AZclzopt , mm

d 
H0, T

Ibeam, A

Ibeam, A

Fig.4. The field profile inside the interaction space of a planar gyrotron for the mode with a single longitudinalvariation m  1 (a). Dependencies of electron efficiency (a), output power and Ohmic losses (b), optimal
interaction length and magnetic field (c) on the injection currentB) Operation at the second cyclotron harmonic.
For the second harmonic operation, we decrease the gap between the plates up to l y  2.3 mm (6  ) that
corresponds to the twelfth (TE12) mode of the planar waveguide. The sheet beam width was chosen equal to thetransverse size of the interaction space of 7.7 mm (20  ). As one can see from Table 1, the efficiency and output
power at the second harmonic are lower comparing it with the first harmonic operation while the Ohmic losses
increase. Nevertheless, these values exceed the calculated parameters of the double-beam gyrotron [9] for thesame injection current.
3D PIC simulations of a planar gyrotron operation at the third cyclotron harmonic
Results in the frame of averaged approach were confirmed by direct simulations using the PIC (particle incell) code CST STUDIO SUITE. In particular, the possibility of an efficient generation at the 3 d harmonic has
been demonstrated in the range of ~ 250-300 GHz (see Fig.5). The sheet electron beam used in the simulations
possesses the following parameters: electron energy of 80 kV, electron current of 15 A, pitch factor of ~ 1. The
distance between the plates was chosen to be 3 mm (~ 2.5 - 3 wavelengths), the width of the plates is 1 cm (about
8 - 10 wavelengths). Simulations show the establishment of a steady-state regime at the 3d cyclotron harmonic

for the guiding magnetic field of 3.35 Т. In this regime the spatial structure of the radiation corresponds to theexcitation of the TE5 mode with high selectivity. For the chosen parameters the efficiency of the generation isabout of 8% and the output power is 50 kW.

a

c

b

d 

Fig.5. Results of PIC simulations for operation of a planar gyrotron at the 3 d cyclotron harmonic: dispersion
diagram (a), spatial structure of the electromagnetic field (b), set-on of the steady-state regime (c) and thecorresponding spectrum of the radiation (d).

References:[1] T. Idehara, H. Tsuchiya, O. Watanabe, La Agusu, and S. Mitsudo, The first experiment of a THz gyrotron with a pulse
magnet, Int. J. Infrared and Millimeter Waves, 27 (3), 319-331 (2006).
[2] M.Yu. Glyavin, A.G. Luchinin, and G.Yu. Golubiatnikov, Generation of 1.5-kW, 1-THz coherent radiation from agyrotron with a pulsed magnetic field, Phys. Rev. Lett. 100, 1, 015101 (2008).
[3] T. Notake, T. Saito, Y. Tatematsu, A. Fujii, S. Ogasawara, La Agusu, I. Ogawa, T. Idehara, and V.N. Manuilov,
Development of a novel high power sub-THz second harmonic gyrotron, Phys. Rev. Lett. 103, 225002 (2009).
[4] V.L. Bratman, Yu.K. Kalynov, and V.N. Manuilov, Large-orbit gyrotron operation in the terahertz frequency range,
Phys. Rev. Lett. 102, 245101 (2009).
[5] T. Idehara, M. Glyavin, A. Kuleshov, S. Sabchevski, V. Manuilov, V. Zaslavsky, I. Zotova, and A. Sedov, A novel THzband double-beam gyrotron for high-field DNP-NMR spectroscopy, Rev. of Sci. Instr., 88, 094708 (2017).
[6] N.S. Ginzburg, I.V. Zotova, A.S. Sergeev, V.Yu. Zaslavsky, and I.V. Zheleznov, High-power terahertz-range planar
gyrotrons with transverse energy extraction, Phys. Rev. Lett., 108, 105101 (2012).
[7] V.Yu. Zaslavsky, N.S. Ginzburg, M.Yu. Glyavin, I.V. Zheleznov, and I.V. Zotova, Three-dimensional particle-in-cellmodeling of terahertz gyrotrons with cylindrical and planar configurations of the interaction space, Physics of Plasmas,
20, 043103 (2013).
[8] N.S. Ginzburg, G.S. Nusinivich, and N.A. Zavolsky, Theory of non-stationary processes in gyrotrons with low Q
resonators, Int. J of Electronics, 61 (6), 881-894 (1986).
[9] N.S. Ginzburg, M.Yu. Glyavin, A.M. Malkin, V.N. Manuilov, R.M. Rozental, A.S. Sedov, A.S. Sergeev, V.Yu.
Zaslavsky, I.V. Zotova and T. Idehara, Improvement of stability of high cyclotron harmonic operation in the doublebeam THz range gyrotrons, IEEE Trans. on Plasma Sci., 44 (8) 1303-1309 (2016).

The first author of this short paper, Professor Naum Ginzburg was a Visiting Professor at the University of Fukui
from November to December 2017. On 15 December 2017 he delivered a talk “Development of Terahertz-Range
Planar Gyrotrons with Transverse Energy Extraction Operating at the Fundamental and High-Order cyclotron
harmonics” at the FIR UF seminar. The paper summarizes the main results presented and discussed there.

NEXT IRMMW-THz CONFERENCECONFERENCE

For up-to-date information, registration, etc. follow the link to the website of IRMMW-THz 2018

OTHER CONFERENCES
19th International Vacuum Electronics ConferenceMonterey, US, 24 - 26 April 2018
http://ivec2018.org/
6th ITG International Vacuum Electronics Workshop 2018
Physikzentrum Bad Honnef (PBH), Bad Honnef (Germany), 6.09.2018 - 07.09.2018https://www.ihe.kit.edu/download/VDE(ITG)_%20WORKSHOP_IVEW%202018_Call_V2.pdf
7th Euro-Asian Pulsed Power Conference (EAPPC) and 22nd International Conference on High-Power Particle
Beams (BEAMS)
Changsha, China, 16-20 September 2018
http://www.eappc-beams2018.org/
The 40th PIERS (Progress In Electromagnetics Research Symposium)
Toyama, Japan, 1 - 4 August 2018
http://piers.org/piers2018Toyama/
13th International Conference on Electron Beam Technologies
Varna, Bulgaria, 13-18 June 2018
http://www.ebtconference.com/index.html
GeMiC 2018 – German Microwave Conference
Konzerthaus Freiburg, Germany, 12-14 March 2018https://www.gemic2018.de/
The 3rd Conference on Microwave and Terahertz Technology (ICMT 2018)
Arnoma Hotel, Bangkok, Thailand, 5-7 January 2018https://waset.org/conference/2018/08/bangkok/ICMT
8th International Workshop on Terahertz Technology and Applications
Kaiserslautern, Germany, 20-21 March 2018https://www.vdi.de/index.php?id=47465
Asia Pacific Microwave Conference
Kyoto, Japan, 6 - 9 November 2018
http://www.apmc2018.org/
International Applied Computational Electromagnetics Society Symposium ACES-2018
Denver, CO, United States, 24-29 March 2018
http://aces-society.org/conference/Denver_2018/
The IEEE International Conference on Computational Electromagnetics ICCEM-2018
Chengdu, China, 27-29 March 2018
http://www.aconf.org/conf_108661.html
International Conference on Terahertz Emission, Metamaterials and Nanophotonics
Hacienda Uxmal Plantation & Museum, Mexico, 25-29 March 2018https://www.mifp.eu/SCHOOLS/TERAMETANANO-3/
International Conference on Microwave and Millimeter Wave Technology (ICMMT2018)
Chengdu, China, 7-11 May 2018

https://www.aconf.org/conf_111318.html
3rd International Conference on Microwave and Photonics (ICMAP 2018)
Dhanbad, India
http://www.icmap2018.org/
IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling andOptimization
Reykjavik, Iceland, 8-10 August 2018
http://nemo-ieee.org/
IEEE MTT-S The International Microwave Biomedical Conference (IMBioC)
Philadelphia, PA , USA, 14-15 June 2018https://www.imbioc-ieee.org/
2nd Asia-Pacific Conference on Plasma Physics AAPPS-DPP2018
Kanazawa, Japan, 12-17 November 2018
http://aappsdpp.org/DPP2018/index.html
International Conference Advanced Laser Technologies (ALT 2018)
Tarragona, Spain, 10-15 September 2018
http://altconference.org/alt18

LIST OF SELECTED RECENT PUBLICATIONS
Bibliography and links to selected recent publications on topics related to the research fieldof the International Consortium and published after October 2017, i.e. after issuing theprevious Newsletter #7. This cumulative list is in chronological order as collected fromvarious bibliographical and alert services
A. Publications by authors from the institutions participating in the International Consortium
Proyavin M.D., Glyavin M.Yu., Manuilov V.N., “Magnetically shielded electron-optical system of a continuous
gyrotron with an operating frequency of 24 GHz,” Journal of Communications Technology and Electronics, vol.
62, n. 10 (2017) 1165-1171. DOI:10.1134/S1064226917100126.
https://rd.springer.com/article/10.1134/S1064226917100126
Gantenbein G., Albajar F., Alberti S., Avramidis K., et al., “Experimental Results of the EU ITER Prototype
Gyrotrons,” EPJ Web Conf., vol. 157 (2017) 03016. DOI: 10.1051/epjconf/201715703016.
https://www.epj-conferences.org/articles/epjconf/pdf/2017/26/epjconf_rfppc2017_03016.pdf
Rozental R.M., Ginzburg N.S., Sergeev A.S., Zotova I.V., Fedotov A.E., Tarakanov V.P., “Gyrotron generationof broadband chaotic radiation under overlapping of high- and low-frequency resonances,” Technical Physics,
vol. 62, n. 10 (2017) 1562-1568. DOI:10.1134/S106378421710019X.
https://rd.springer.com/article/10.1134/S106378421710019X
Ivanov O., Kuzikov S.V., Vikharev A.A., Vikharev A.L., Lobaev M.A., “The Diamond Window with BoronDoped Layers for the Output of Microwave Radiation at High Peak and Average Power Levels,” Radiophys
Quantum Electronics (2017). DOI:10.1007/s11141-017-9809-8.
https://rd.springer.com/article/10.1007%2Fs11141-017-9809-8#citeas

Melnikova M.M., Rozhnev A.G., Ryskin N.M., Tatematsu Y., Fukunari M., Yamaguchi Y., Saito T.,“Electromagnetic Modeling of a Complex-Cavity Resonator for the 0.4-THz Second-Harmonic FrequencyTunable Gyrotron,” IEEE Trans. on Electron Devices, (2017). DOI: 10.1109/TED.2017.2764874.
http://ieeexplore.ieee.org/document/8091119/
Toda Y., Ishiyama S., Khutoryan E., Idehara T., Matsuishi S., Sushko P.V., Hosono H., “Rattling of Oxygen Ionsin a Sub-Nanometer Sized Cage Convert Terahertz Radiation to Visible Light,” ACS Nano, (2017). DOI:
10.1021/acsnano.7b06277.
http://pubs.acs.org/doi/10.1021/acsnano.7b06277
Yuvaraj S., Illy S., Kartikeyan M.V., “Electron Gun and Output Coupling System for a 220-/251.5-GHz, 2-MW
Triangular Corrugated Coaxial Cavity Gyrotron,” IEEE Trans. Electron Devices, (2017). DOI:
10.1109/TED.2017.2764942.
http://ieeexplore.ieee.org/document/8093744/
Khutoryan E.M., Kovshov Yu.S., Likhachev A.S., Ponomarenko S.S., Kishko S.A., Lukin K.A., Zavertanniy
V.V., Kudinova T.V.. Vlasenko S.A., Kuleshov A.N., Idehara T., "Excitation of Hybrid Space-Surface Waves in
Clinotrons with Non-uniform Grating," Journal of Infrared, Millimeter, and Terahertz Waves, vol. 39 (2018) 236249. DOI:10.1007/s10762-017-0453-3.
https://rd.springer.com/article/10.1007%2Fs10762-017-0453-3
Goldenberg A.L., Glyavin M.Yu., Leshcheva K.A., Manuilov V.N., "Nonadiabatic Electron-Optical System of aTechnological Gyrotron," Radiophysics and Quantum Electronics, vol 60, n. 5 (2017) 395-400.
DOI:10.1007/s11141-017-9808-9.
https://rd.springer.com/article/10.1007%2Fs11141-017-9808-9
Bratman V.L., Fedotov A.E., Fokin A.P., Glyavin M.Yu., Manuilov V.N., and Osharin I.V., “Operation of a subterahertz CW gyrotron with an extremely low voltage,” Physics of Plasmas, vol. 24, n. 11 (2017) 113105.
DOI:10.1063/1.5000481.
http://aip.scitation.org/doi/10.1063/1.5000481
Kalaria P.C., “Feasibility and Operational Limits for a 236 GHz Hollow-Cavity Gyrotron for DEMO,” Institut
für Hochleistungsimpuls- und Mikrowellentechnik (IHM), Dissertation, (2017). ISBN: 978-3-7315-0717-8. DOI:
10.5445/KSP/1000073581.
https://publikationen.bibliothek.kit.edu/1000073581
Bratman V.L., Fedotov A.E., Kalynov Y.K., Osharin I.V., Zavolsky N.A., "Smooth Wideband Frequency Tuning
in Low-Voltage Gyrotron With Cathode-End Power Output," IEEE Trans. on Electron Devices,vol. 64, n.12(2017) 5147-5150. DOI:10.1109/TED.2017.2766281.
http://ieeexplore.ieee.org/document/8098610/
Matsuki Y., Fujiwara T., “Advances in High-Field DNP Methods,” In: The Nuclear Magnetic Resonance Societyof Japan (eds) Experimental Approaches of NMR Spectroscopy (Springer, Singapore, 2018) pp. 91-134.
DOI:10.1007/978-981-10-5966-7_4. Print ISBN, 978-981-10-5965-0, Online ISBN 978-981-10-5966-7.
https://rd.springer.com/chapter/10.1007%2F978-981-10-5966-7_4
Samsonov S.V., Denisov G.G., Mishakin S.V., “3D simulations of a Ka-band gyro-TWT with power up to 10
kW from the cathode to the end of interaction space,” Zhurnal Radioelektroniki (Journal of Radio Electronics),
n. 11 (2017) (In Russian). http://jre.cplire.ru/jre/nov17/10/text.pdf.
Dumbrajs O., Idehara T., "Theoretical Study on the 1.185-THz Third Harmonic Gyrotron," Journal of Infrared,
Millimeter, and Terahertz Waves, (2017) pp. 6. DOI:10.1007/s10762-017-0459-x.
https://rd.springer.com/article/10.1007%2Fs10762-017-0459-x

Belousov V.I., Vershkov V.A., Denisov G.G., et al., “A five-channel quasi-optical multiplexer of 12- to 90-GHz
frequency range,” Tech. Phys. Lett. vol. 43 (2017) DOI:10.1134/S1063785017110189
https://rd.springer.com/article/10.1134%2FS1063785017110189
Idehara T., Sabchevski S.P. "Development and Application of Gyrotrons at FIR UF," IEEE Transactions on
Plasma Science, (2018) pp. 8. DOI: 10.1109/TPS.2017.2775678.
http://ieeexplore.ieee.org/document/8126265/
Afalla J.P.C., de los Reyes A., Mag-usara V.K., Lopez L.P., Yamamoto K., Tani M., Somintac A.S., Salvador
A.A., Estacio E.S., "Defect-related temperature dependence of THz emission from GaAs/AlGaAs MQWs grownon off- and on-axis substrates," AIP Advances, vol. 7, n. 12 (2017)125210. DOI:10.1063/1.5004597.
http://aip.scitation.org/doi/10.1063/1.5004597
Nanni E., Jawla S., Lewis S.M., Shapiro M.A., Temkin R.J., "Photonic-band-gap gyrotron amplifier withpicosecond pulses," Applied Physics Letters, vol. 111, n. 23 (2017)233504. DOI:10.1063/1.5006348
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Tsun-Hsu Chang, Hsin-Yu Yao, Bo-Yuan Su, Wei-Chen Huang, and Bo-Yuan Wei, “Nonlinear oscillations of
TM-mode gyrotrons,” Physics of Plasmas, vol. 24 (2017) 122109. DOI:10.1063/1.5008307.
http://aip.scitation.org/toc/php/24/12
Ishikawa Y., Ohya K., Fujii Y., Koizumi Y., Miura S., Mitsudo S., Fukuda A., Asano T., Mizusaki T., Matsubara
A., Kikuchi H., Yamamori H., "Development of a Millimeter-Wave Electron-Spin-Resonance Measurement
System for Ultralow Temperatures and Its Application to Measurements of Copper Pyrazine Dinitrate," Journalof Infrared, Millimeter, and Terahertz Waves, (2017). DOI:10.1007/s10762-017-0460-4.
https://link.springer.com/article/10.1007%2Fs10762-017-0460-4
Abubakirov E.B., Guznov Y.M., Kuzikov S.V., Shevchenko A.S., Vikharev A.A., Zapevalov S.A., "QuasiOptical Input Mode Coupler for a Ka-Band Multimegawatt Gyroklystron," IEEE Trans. on Microwave Theory
and Techniques, (2017) DOI:10.1109/TMTT.2017.2772917.
http://ieeexplore.ieee.org/abstract/document/8141926
Zotova I.V., Denisov G.G., Ginzburg N.S., Sergeev A.S., Rozental R.M., “Time-domain theory of low-Q
gyrotrons with frequency-dependent reflections of output radiation,” Physics of Plasmas, vol. 25 (2018) 013104.
DOI: 10.1063/1.5008666.
http://aip.scitation.org/doi/pdf/10.1063/1.5008666
Avramidis K.A., et al., "Numerical Studies on the Influence of Cavity Thermal Expansion on the Performance ofa High-Power Gyrotron," IEEE Trans. on Electron Devices, (2018). DOI:10.1109/TED.2017.2782365.
http://ieeexplore.ieee.org/document/8252918/
Chelis I.G., Avramidis K.A., Ioannidis Z.C. Tigelis I.G., "Improved Suppression of Parasitic Oscillations in
Gyrotron Beam Tunnels by Proper Selection of the Lossy Ceramic Material," IEEE Trans. on Electron Devices,(2018) pp. 1-7. DOI: 10.1109/TED.2017.2784198.
http://ieeexplore.ieee.org/document/8246705/
Tanaka K., Nishiura N., Kubo S., Shimozuma T., Saito T., Moseev D., Abramovic I., "154 GHz collective
Thomson scattering in LHD," Journal of Instrumentation, vol. 13, n. 1 (2018) DOI:
10.1088/17480221/13/01/C01010.
http://iopscience.iop.org/article/10.1088/1748-0221/13/01/C01010
Pagonakis I.G., Illy S., Ioannidis Z.C., Rzesnicki T., Avramidis K.A., Gantenbein G., Kobarg T., Piosczyk B.,
Thumm M., Jelonnek J., "Numerical Investigation on Spent Beam Deceleration Schemes for Depressed Collectorof a High-Power Gyrotron, IEEE Trans. on Electron Devices, (2018) pp. 1-6. DOI:10.1109/TED.2017.2784185.

http://ieeexplore.ieee.org/document/8259483/
Kovshov Y.S., Ponomarenko S.S., Kishko S.A., Khutoryan E.M., Kuleshov A.N., "Numerical Simulation andExperimental Study of Sub-THz and THz CW Clinotron Oscillators," IEEE Trans. on Electron Devices, (2018)
pp. 1-6. DOI: 10.1109/TED.2018.2792258.
http://ieeexplore.ieee.org/document/8267495/
Ginzburg N.S., Vilkov M.N., Kocharovskaya E.R., Sergeev A.S., "Generation of high-power broadband terahertz
radiation during stimulated backscattering of the pump wave by an intense relativistic electron beam," Physics ofPlasmas, vol. 24, n. 12 (2017) 123112. DOI:10.1063/1.5003899.
http://aip.scitation.org/doi/pdf/10.1063/1.5003899
Dumbrajs O., Nusinovich G.S., “Efficiency of gyrotrons with a tapered magnetic field in the regime of soft selfExcitation,” Physics of Plasmas, vol. 25 (2018) 013121 (2018). DOI: 10.1063/1.5019974.
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Z. C. Ioannidis et al., "An Improved Diagnostic Device for Magnetron Injection Guns of High-Power Gyrotrons,"
IEEE Trans. on Electron Devices, (2018). DOI:10.1109/TED.2018.2793341.
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Abubakirov E.B., Denisenko A.N., Konyushkov A.P.,Osharin I.V., Rozental R.M., Tarakanov V.P., Fedotov
A.E., "Developing a high-current relativistic millimeter-wave gyrotron," Bulletin of the Russian Academy of
Sciences: Physics, vol. 82, n.1 (2018) 48-52. DOI:10.3103/S1062873818010033.
https://link.springer.com/article/10.3103%2FS1062873818010033
B. Publications by other authors worldwide
Yeh Y.S., Hung C.L., Zheng C.Y., Kao W.J.,Chiang P.Y., Chen Y.C.,"A study of a terahertz gyrotron travelingwave amplifier," Physics of Plasmas, vol. 24, n. 10 (2017) 103126. DOI:10.1063/1.5001389.
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Qiao Liu , Yinghui Liu, Xinjian Niu, Jianhua Xu, and Jianing Zhao, "Theoretical Investigation on a
Multifrequency Multimode Gyrotron at Ka-Band," IEEE Tran. Plasma Science, (2017).
DOI:10.1109/TPS.2017.2757060.
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Masayuki Takahashi “Development of Plasma Fluid Model for a Microwave Rocket Supported by a Magnetic
Field,” Journal of Physics: Conference Series, vol. 905, n. 1 (2017) 012024. DOI: 10.1088/17426596/905/1/012024.
http://stacks.iop.org/1742-6596/905/i=1/a=012024
Artem’ev K.V., Batanov G.M., Berezhetskaya N.K., Davydov A.M., Kossyi I.A., Nefedov V.I., Sarksyan K.A.,
Kharchev N.K., “Subthreshold self-sustained discharge initiated by a microwave beam in a large volume of highpressure gas,” Journal of Physics: Conference Series, vol. 907, n. 1 (2017) 012022. DOI: 10.1088/17426596/907/1/012022.
http://stacks.iop.org/1742-6596/907/i=1/a=012022
Alberti S., Genoud J., Goodman T., Hogge J.-Ph., et al, “Recent progress in the upgrade of the TCV EC-systemwith two 1MW/2s dual-frequency (84/126GHz) gyrotrons,” EPJ Web Conf. vol. 157 (2017) 03001. DOI:
10.1051/epjconf/201715703001.
https://www.epj-conferences.org/articles/epjconf/pdf/2017/26/epjconf_rfppc2017_03001.pdf
He W., Donaldson C.R., Zhang L., Ronald K., Phelps A.D.R., Cross A.W. “Broadband Amplification of LowTerahertz Signals Using Axis-Encircling Electrons in a Helically Corrugated Interaction Region,” Phys. Rev.

Lett., vol. 119, n. 18 (2017) 184801. DOI:10.1103/PhysRevLett.119.184801.
https://link.aps.org/doi/10.1103/PhysRevLett.119.184801
Cole N., Antonsen T.M., “Electron Cyclotron Resonance Gain in the Presence of Collisions,” IEEE Trans. Plasma
Science, (2017) pp. 10. DOI: 10.1109/TPS.2017.2759269.
http://ieeexplore.ieee.org/document/8070450/
Pan Shi, Du Chao-Hai, Qi Xiang-Bo, Liu Pu-Kun, “Broadband terahertz-power extracting by using electron
cyclotron maser,” Scientific Reports, vol. 7, n.1 (2017) 7265. DOI:10.1038/s41598-017-07545-6.
https://www.nature.com/articles/s41598-017-07545-6
Lu F., Zhang C., Grieser M., Wang Y., Lu S., Zhao G., “Study of rectangular beam folded waveguide travelingwave tube for terahertz radiation,” Physics of Plasmas, vol. 24, n. 10 (2017) 103132. DOI: 10.1063/1.5008287.
http://aip.scitation.org/doi/abs/10.1063/1.5008287
Thanigaiarul K., “Electron Beam in Gyrotrons Diagnostics Microwave,” Indian Journal of Forensic Medicine &Toxicology, vol. 11, n. 2 (2017) 437-439. DOI: 10.5958/0973-9130.2017.00160.8
http://www.indianjournals.com/ijor.aspx?target=ijor:ijfmt&volume=11&issue=2&article=105
Park H.K., “Role of Radio Frequency and Microwaves in Magnetic Fusion Plasma Research,” Journal of
Electromagnetic Engineering and Science, vol. 17, n. 4 (2017) 169-177. DOI:10.26866/jees.2017.17.4.169.
http://jees.kr/upload/pdf/jees-2017-17-4-169.pdf
Sawant A., Yu D., Kim D., Choe M.-S., Choi E., “Generation and Validation of Topological Charges of HighPower Gyrotron Orbital Angular Momentum Beams From Phase Retrieval Algorithm,” Trans. on Terahertz
Science and Technology, (2017). DOI: 10.1109/TTHZ.2016.2637868.
http://ieeexplore.ieee.org/document/7802640/
Shcherbinin V.I., Tkachova T.I., Tkachenko V.I., "Improved Cavity for Broadband Frequency-Tunable
Gyrotron," IEEE Trans. on Electron Devices, (2017). DOI: 10.1109/TED.2017.2769219.
http://ieeexplore.ieee.org/abstract/document/8107664/
Aronov S., Einat M., Furman O., Pilossof M., Komoshvili K., Ben-Moshe R., Yahalom A., Levitan J.,"Millimeter-wave insertion loss of mice skin," Journal of Electromagnetic Waves and Applications, (2017) 09205071. DOI:10.1080/09205071.2017.1404941.
http://www.tandfonline.com/doi/full/10.1080/09205071.2017.1404941
Sapronova T.M., Syrovoi V.A., "Formation of a ribbon electron beam of a planar gyrotron in the end region andnear the edge of the cathode," Journal of Communications Technology and Electronics, vol. 62, n. 11 (2017)
1271-1280. DOI:10.1134/S1064226917100138.
https://link.springer.com/article/10.1134/S1064226917100138
Sapronova T.M., Syrovoi V.A., "Configuration of the thermal gap in magnetron-injection guns complying withthe hydrodynamic flow model," Journal of Communications Technology and Electronics, vol.62, n. 11 (2017)
1281-1290. DOI:10.1134/S106422691710014X.
https://link.springer.com/article/10.1134/S106422691710014X
Sawant A., Choi E.M."Competition-free second harmonic mode THz orbital angular momentum gyrotron withdual-mode operation by a perturbed cavity, "Physics of Plasmas, vol. 24, n. 11 (2017) 113109.
DOI:10.1063/1.5002732.
http://aip.scitation.org/doi/10.1063/1.5002732
Singh R.K., “Analysis for beam positioning in a disc-loaded gyro-TWT amplifier,” J Comput Electron (2017).
DOI:10.1007/s10825-017-1114-4.

https://link.springer.com/article/10.1007/s10825-017-1114-4
Guan Xiaotong, Fu Wenjie, Yan Yang, "Demonstration of a High-Order Mode Input Coupler for a 220-GHz
Confocal Gyrotron Traveling Wave Tube,” Journal of Infrared, Millimeter, and Terahertz Waves, (2017).
DOI:10.1007/s10762-017-0458-y.
https://link.springer.com/article/10.1007/s10762-017-0458-y
Diana Gamzina, Xiang Li, Christian Hurd, Ye Tang, Xuejiao Huang, Yuan Zheng, Logan Himes, Michelle
Gonzalez, Hanyan Li, Pan Pan, Rosa Letizia, Jinjun Feng, Neville C. Luhmann, Claudio Paoloni, "Backward
wave oscillator for high power generation at THz frequencies", Proc. SPIE 10383, Terahertz Emitters, Receivers,
andApplications
VIII,
1038303(23
August2017).
DOI
10.1117/12.2273256;
http://dx.doi.org/10.1117/12.2273256
Shengpeng Yang, Qing Zhou, Changjian Tang, Shaoyong Chen, “Terahertz electromagnetic radiation based on
the interaction between a self-modulated electron beam and plasma wakefield,” Physics of Plasmas, vol. 24, n.
12 (2017) 123107. DOI: 10.1063/1.5003134.
http://aip.scitation.org/doi/abs/10.1063/1.5003134
Donaldson C.R., Zhang L., Beardsley M., Harris M., Huggard P.G., He W., "CNC Machined HelicallyCorrugated Interaction Region for a THz Gyrotron Traveling Wave Amplifier," IEEE Trans. On Terahertz
Science and Technology, (2017). DOI:10.1109/TTHZ.2017.2778944.
http://ieeexplore.ieee.org/document/8214232/
Yao Y., Wang JLiu., G., Li H., Jiang W., Luo Y., "HE₀₄ Mode Exciters With Flat Transmission and High Mode
Purity for Confocal Gyro-TWAs," IEEE Trans. on Electron Devices, (2017). DOI: 10.1109/TED.2017.2779321.
http://ieeexplore.ieee.org/abstract/document/8207764/
Luo L., Du C.H., Qi X.B., Li Z.D., Pan S., Huang M.G., Liu P.K., "Controllable Thermal-Frequency Tuning ofa Terahertz Gyrotron," IEEE Trans. on Electron Devices, (2017). DOI:10.1109/TED.2017.2778304.
http://ieeexplore.ieee.org/document/8240959/
Luo L., Du C.H., Qi X.B., Li Z.D., Pan S., Huang M.G., Liu P.K., "Controllable Thermal-Frequency Tuning ofa Terahertz Gyrotron," IEEE Trans. on Electron Devices, (2017). DOI:10.1109/TED.2017.2778304
http://ieeexplore.ieee.org/abstract/document/8240959/
Karetnikova T.A., Rozhnev A.G., Ryskin N.M., Fedotov A.E., Mishakin S.V., Ginzburg N.S., "Gain Analysis of
a 0.2-THz Traveling-Wave Tube with Sheet Electron Beam and Staggered Grating Slow Wave Structure," IEEE
Trans.on Electron Devices, (2018). DOI:10.1109/TED.2017.2787960.
http://ieeexplore.ieee.org/document/8252742/
Sergey L. Veber, Sergey V. Tumanov, Elena Yu. Fursova, Oleg A. Shevchenko, Yaroslav V. Getmanov, Mikhail
A. Scheglov, Vitaly V. Kubarev, Daria A. Shevchenko, Iaroslav I. Gorbachev, Tatiana V. Salikova, Gennady N.
Kulipanov, Victor I. Ovcharenko, Matvey V. Fedin, “X-band EPR setup with THz light excitation of Novosibirsk
Free Electron Laser: goals, means, useful extras,” Journal of Magnetic Resonance, Available online 12 January
2018. DOI:10.1016/j.jmr.2018.01.009.
https://www.sciencedirect.com/science/article/pii/S1090780718300211
Akhmadullina N.S., et al., “Synthesis of oxide and nitride ceramics in high-power gyrotron discharge,” J. Phys.:Conf. Ser., vol. 941 (2017) 012034. DOI: 10.1088/1742-6596/941/1/012034.
http://iopscience.iop.org/article/10.1088/1742-6596/941/1/012034
Xi Hongzhu, Wang Jianguo, He Zhaochang, Zhu Gang, Wang Yue, Wang Hao, Chen Zaigao, Li Rong, Liu
Luwei, "Continuous-wave Y-band planar BWO with wide tunable bandwidth," Scientific Reports, vol. 8, n. 1
(2018) 348. DOI:10.1038/s41598-017-18740-w.

https://www.nature.com/articles/s41598-017-18740-w
Lee I., Sawant A., Choe M.S., Lee, D.-J., Choi E.,"Accurate identification of whispering gallery mode patternsof gyrotron with stabilized electro-optic imaging system," Physics of Plasmas, vol. 25, n. 1 (2018) 013116.
DOI:10.1063/1.5017558.
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Liu Q., et al., "Thermoanalysis and Its Effect on the Multimode Beam-Wave Interaction for a 0.24-THz,
Megawatt-Class Gyrotron," IEEE Trans. on Electron Devices, vol. 65, n. 2 (2018) 704-709.
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R. Yan et al., "Automatic Hot-Test System for High Average/Continuous-Wave Power Gyro-TWTs," in IEEE
Trans. on Electron Devices, (2018) pp. 1-7. DOI:10.1109/TED.2018.2790174.
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G. X. Shu et al., "Demonstration of a Planar W-band, kW-level Extended Interaction Oscillator Based on a
Pseudospark-sourced
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Electron
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Electron Device Letters, (2018). DOI:10.1109/LED.2018.2797067.
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Romanenko S., Begley R., Harvey A.R., Hool L., Wallace V.P. “The interaction between electromagnetic fields
at megahertz, gigahertz and terahertz frequencies with cells, tissues and organisms: risks and potential,” J. R. Soc.
Interface, vol. 14 (2017) 20170585. DOI:10.1098/rsif.2017.0585.
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Ikeda R., Oda Y., Kobayashi T., Terakado M., Kajiwara K., Takahashi K., Moriyama S., Sakamoto K.,“Development of 170 GHz, 1 MW gyrotron with high-order TE31,11 mode oscillation for ITER EC system,”
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Ashrafi A., Hasanbeigi A., Mehdian H., "Dispersion and growth characteristics in a circular waveguide loadedwith alternate metal and dielectric discs," AIP Advances, vol. 8, n. 1 (2018) 015322. DOI:10.1063/1.5017747
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Sun W., Yu S., Wang Z., Yang Y., "Linear and Nonlinear Analyses of a 0.34-THz Confocal Waveguide GyroTWT," IEEE Trans. on Plasma Science, (2018). DOI:10.1109/TPS.2018.2794380.
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C. Patents
High Voltage DC Power Supply for High Power Radio Frequency Amplifiers
United States Patent Application 20170310111
Inventors: Badapanda, Manmath Kumar (Indore, IN)
Publication Date:10/26/2017

http://www.freepatentsonline.com/y2017/0310111.html
Strong-Magnetic-Focused Magnet System with Terahertz Source
United States Patent Application 20170372824
Inventors: Wang, Qiuliang (Beijing, CN), Hu, Xinning (Beijing, CN), Dai, Yinming (Beijing, CN)
Publication Date: 12/28/2017
http://www.freepatentsonline.com/y2017/0372824.html
Waveguide system for slot radiating first electromagnetic waves that are combined into a non-fundamental
wave mode second electromagnetic wave on a transmission medium
Inventors: Henry, Paul Shala (Holmdel, NJ, US), Bennett, Robert (Southold, NY, US), Barzegar, Farhad(Branchburg, NJ, US), Gerszberg, Irwin (Kendall Park, NJ, US), Barnickel, Donald J. (Flemington, NJ, US),
Willis III, Thomas M. (Tinton Falls, NJ, US), Guntin, Ed (Barrington, IL, US)
Publication Date: 01/09/2018
http://www.freepatentsonline.com/9865911.html

NEW BOOKS“Experimental Approaches of NMR Spectroscopy,” Editors: The Nuclear Magnetic Resonance Society of Japan,(Springer, Singapore, 2018). Print ISBN 978-981-10-5965-0, Online ISBN 978-981-10-5966-DOI: 10.1007/978981-10-5966-7
https://rd.springer.com/book/10.1007%2F978-981-10-5966-7
Dattoli G., Doria A., Sabia E., Artioli M., "Charged Beam Dynamics, Particle Accelerators and Free Electron
Lasers" (IOP Publishing, 2017). DOI:10.1088/978-0-7503-1239-4.
http://iopscience.iop.org/book/978-0-7503-1239-4.1088/978-0-7503-1239-4
Kesari V., Basu B.N, High Power Microwave Tubes: Basics and Trends, Volume 2 (Morgan & Claypool
Publishers, 2018). Online ISBN: 978-1-6817-4704-0, Print ISBN: 978-1-68174-789-7. DOI:10.1088/978-16817-4704-0.
Grigoriev A.D., Ivanov V.A., Molokovsky S.I., Microwave Electronics, (Springer Series in Advanced
Microelectronics, 2018). SBN 978-3-319-68890-9.
Peter Hawkes, and Erwin Kasper, Principles of Electron Optics 2nd Edition (Academic Press, 2018). eBook
ISBN: 9780081026830, Book ISBN: 9780081026823.
Yang R., Li H., Li S., Zhang P., Tan L., Gao X., Kang X., High-Resolution Microwave Imaging (Springer, 2018).
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Nair R.U., Dutta M., P.S., M.Y., Venu K.SEM, Material Characterization Techniques for Metamaterials,(Springer Briefs in Computational Electromagnetics, 2018). ISBN 978-981-10-6517-0.
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.

NEWS FROM THE NET (OUR BROADER HORIZONS)
Rattling motion of oxygen ions converts the terahertz rays generated by a gyrotron tovisible light
In a recently published paper, which presents the results from the experiments carried out at the ResearchCenter for Development of Far-Infrared Region at the University of Fukui (FIR UF Center), it has been
demonstrated that the irradiation of nanoscale cages of Ca12Al14O33 crystal (called mayenite) converts the CWTerahertz radiation produced by a gyrotron to a visible light. The authors explain this by the fact that thesecrystallographic cages are partially occupied with weakly bonded oxygen ions and have a narrow conduction
band that can be populated with localized, albeit mobile electrons. Under the influence of the electromagnetic
field of the terahertz wave, the encaged oxygen ions exercise a rattling motion (vibration), which promotes anelectron transfer of the electrons to the neighboring vacant cages. At sufficiently high irradiating power (of theorder of several tens of Watts) the combined effect of several phenomena (coupling between the forced rattling
motion in a confined space, excitation and ionization of the oxygen species, and most notably the corresponding
recombination processes) is an intense emission of bright visible light. Schematically, the observed effect is
illustrated in the following figure (courtesy of ACS Publications):

Schematics of the observed phenomenon and a detail of the experimental setup
As pointed out by Science Daily (November 28, 2017) , “The finding is a breakthrough for functional materials
research and could lead to the development of a new kind of terahertz detector.” Further, the article in Science
Daily emphasizes that “The study is an example of strategic research on functional materials under the Element
Strategy initiative supported by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT)
and the Japan Science and Technology Agency (JST).” In an interview for the same on-line edition, Hideo
Hosono of Materials Research Center for Element Strategy, Tokyo Tech says: “"Our group has been

concentrating on the cultivation of new functionalities using abundant elements, but it's the first time for me tofocus on ionic motion - this is completely new. Right now, our material is good at detecting strong terahertz
radiation. The challenge will be how to adjust the sensitivity."This breakthrough result has become possible due to the remarkable progress in the development of highpower, terahertz range gyrotrons at the FIR UF Research Center demonstrated recently. These gyrotrons haveopened the road to many novel and pioneering applications in the fundamental physical studies and high-power
terahertz science and technologies.
Please access the original article at ACS NANO:
Yoshitake Toda, Shintaro Ishiyama, Eduard Khutoryan, Toshitaka Idehara, Satoru Matsuishi, Peter V. Sushko,
Hideo Hosono, “Rattling of Oxygen Ions in a Sub-Nanometer-Sized Cage Converts Terahertz Radiation to
Visible Light,” ACS Nano, 2017. DOI: 10.1021/acsnano.7b06277.
Please access information and comments about this publication also at the links below:
Tokio Institute of Technology
Nanowerk Newsletter Email Digests
PhotonicsViews
PhysOrg

News from the Internet Portal Scientific Russia
Multi-megawatt millimeter-wave gyrotron(Visit: https://scientificrussia.ru/articles/multimegavattnyj-millimetrovyj-girotron (in Russian)
The range of millimeter waves has always been of particular interest for the physical research. The length ofthese waves is already so small that their propagation occurs in much the same way as light waves, which makes
it possible to build on millimeter waves, for example, effective high-resolution radar systems. On the other hand,in this range there are characteristic frequencies of radiation absorption by various substances, therefore thesewaves are extremely interesting for spectroscopy. Prospective schemes of charged particle accelerators also relay
on millimeter-wave radiation in order to realize high rates of acceleration. Effective sources of intense radiationin the short-wave part of the millimeter range are the gyro-resonance devices, in particular, the gyrotrons. Their
operation is based on the creation of conditions for coherent radiation of electrons rotating in an external magnetic
field. Modern gyrotrons for plasma heating in the reactors for controlled thermonuclear fusion provide an output
power of up to 2 MW in continuous mode (CW) at a frequency of 170 GHz. A further increase in the gyrotron
power is possible increasing the energy of the electron beam up to the levels of hundreds of thousands of electron
Volts, which means a transition to the region of relativistic energies. For a long time, it was believed that in thisregion the efficiency of gyrotrons is significantly reduced. However, detailed numerical simulation of electronwave interaction processes in the gyrotron resonators has shown, that irrespective of the electron energy,
conditions can be realized in which even in highly relativistic gyrotrons the efficiency reaches 35-45%. This was
confirmed experimentally in the Institute of Applied Physics of the Russian Academy of Sciences, where
gyrotrons operating at a wavelength of 3 and 1 cm with a record-high output power values of about 10 MW havebeen developed. The experience, gained during the research on such such devices has made it possible to agyrotron with similar characteristics in the 3-mm wavelength range.
The 3-mm relativistic gyrotron (see the photo) was realized on the basis of the pulse-periodic electronic
accelerator "Saturn-F". An electron beam with a particle energy of 250 keV and a current of 90-100 A with apulse duration of 1 μs was formed in the accelerator. The beam propagated in a magnetic field with a maximum
field intensity up to 5T, which was created by a superconducting magnet.
As the working mode of the gyrotron, a rotating TE 12,5 mode of a circular waveguide was selected. Such highorder mode has been used for the first time in a relativistic gyrotron. The numerical simulations have shown thepossibility of obtaining output power at a level of several megawatts with an electron efficiency of about 35%.
In the developed gyrotron (in contrast to the long-wavelength devices realized earlier) an internal quasi-opticalmode converter is used, which forms a Gaussian wave beam with a conversion efficiency of more than 95%.

During the experiments with a magnetic field values set close to the cyclotron resonance for the working mode,
the gyrotron demonstrated stable generation at a frequency close to that expected. The operational performanceof the gyrotron was optimized for a set of control parameters, the main ones being the intensity of the magnetic
field in the resonator, the rotational velocity of the electrons, and the radius of the beam in the working space.
The maximum output pulse power observed in the experiment was 5.6 MW at 94.4 GHz with an efficiency of
about 20%.

Photo of the relativistic gyrotron, installed on the experimental stand "Saturn-F"
E.B. Abubakirov,
Leading Researcher of IAP RAS
For more detail about the progress in the development of relativistic gyrotrons, please access the recently
published paper:
Abubakirov E.B., Denisenko A.N., Konyushkov A.P.,Osharin I.V., Rozental R.M., Tarakanov V.P., Fedotov
A.E., "Developing a high-current relativistic millimeter-wave gyrotron," Bulletin of the Russian Academy of
Sciences: Physics, vol. 82, n.1 (2018) 48-52. DOI:10.3103/S1062873818010033.
https://link.springer.com/article/10.3103%2FS1062873818010033

The world's first serial production gyrotron for ITER was developed by Nizhny Novgorod
scientists(Visit: https://scientificrussia.ru/partners/institut-prikladnoj-fiziki-ran/pervyj-v-mire-serijnyj-girotron-dlya-iter(in Russian)
In October 2017, members of the international commission, which included managers and specialists of theRussian Agency "ITER" and the International Organization "ITER" tested the device, after which a protocol was
signed with the resolution "adopted." Gyrotrons for ITER are developed by several international collaborations:
the EU countries, India, the Russian Federation and Japan. In total, the ITER facility will use 24 megawatt
gyrotron complexes with a frequency of 170 GHz and 1 MW output power of each unit. At least 8 of them willbe Russian.
The gyrotron complex is a sophisticated facility that includes about 30 different systems (a cryogen-freesuperconducting magnet, other auxiliary magnets, power supplies, cooling system, control system, etc.) that are
being developed by an interdisciplinary research team. But the heart of the complex is a gyrotron - a source ofpowerful coherent electromagnetic radiation operating in the millimeter wavelength range. It should be
mentioned that the priority in the invention of the gyrotron belongs to the scientists from the IAP RAS. Today,
more than half of the existing experimental plasma heating plants in the world are equipped with Nizhny
Novgorod’s gyrotrons, for the production of which the Scientific and Production Enterprise GIKOM wasestablished twenty-five years ago. The gyrotron complex for the International Project "ITER" demanded fromthe developers a serious and long cycle of research in order to satisfy the requirements imposed by the ITER
project. The prototype complex with the necessary parameters (output power of 1 MW, frequency of 170 GHz,
efficiency 50%, and a pulse duration 1000 s) Nizhny Novgorod created in 2015, the first of all countries
participating in the project.

The photo shows the world's first serial gyrotron complex for the International Thermonuclear Reactor "ITER"
created in Nizhny Novgorod (Russia) by scientists of the Institute of Applied Physics of the Russian Academy of
Sciences in cooperation with the Scientific and Production Enterprise "GIKOM" and the company "RTSoft".

Novel Broadband Gyrotron Travelling Wave Amplifier (gyro-TWA) with an AxisEncircling Electron Beam and a Helically Corrugated Interaction Region
Recently, researchers from the Department of Physics, University of Strathclyde, UK and SUPA (Scottish
Universities Alliance in Physics) have published a paper1 in Physical Review Letters, which presents
experimental results of a broadband, high power, gyro-TWA operating in the 75-110 GHz frequency band andbased on a helically corrugated interaction region. It utilizes an axis-encircling (aka uniaxial) electron beam withan energy of 55 keV and current of 1.5 A, which interacts resonantly with a traveling TE2,1 at the second harmonicof the cyclotron frequency achieving broadband amplification. The gyro-TWA demonstrates a 3-dB gain
bandwidth with at least 5.5 GHz in the experimental measurement with 9 GHz predicted for a wideband drive
source with a measured unsaturated output power of 3.4 kW and a gain of 36-38 dB.
This remarkable results demonstrate the potential of combining two advanced concepts, namely dispersion
engineering (which allows to obtain an appropriate, close to the “ideal”, dispersion diagram in a threefold
helically corrugated waveguide) and the interaction with an axis-encircling beam produced by a cusp electrongun. The authors claim that such approach may allow a gyro-TWA to operate at 1 THz.
For an access to the original paper (published by the American Physical Society under the terms of the Creative
Commons Attribution 4.0 International license.) at publisher’s website please follow the link.
He W., Donaldson C.R., Zhang L., Ronald K., Phelps A. D. R., Cross A.W. “Broadband amplification of lowterahertz signals using axis-encircling electrons in a helically corrugated interaction region,” Physical Review
Letters, 119(18) (2017) 184801. DOI: 10.1103/PhysRevLett.119.184801.
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