Olgerts DUMBRAJS

Born: February 16, 1942, Riga, Latvia

• Nuclear Physics
• Theoretical and Statistical Physics
• Plasma Physics
• Radio Physics (generation of infrared and millimeter waves)
• Deterministic Chaos
• Applied Mathematics

• 1960-1966 B.S.+M.S. degrees: Dept. of Physics, Latvian State University, Riga, Latvia
• 1971 PhD degree: Moscow State University, Russia. Title of Thesis: ''Model independent determination of real parts of hadron-hadron forward scattering amplitudes.''

• 1971-1976 Research worker at the Joint Institute for Nuclear Research, Dubna, Russia.
• 1977-1978 Research worker at the Helsinki University, Finland.
• 1978-1979 Research worker at the Institutes for Nuclear Research in Zürich, Geneva, and Paris.
• 1979-1980 Professor at the Aarhus University, Aarhus, Denmark.
• 1979-1983 Research worker at the University Karlsruhe, Karlsruhe, Germany.
• 1983-1992 Group leader at the University Hamburg-Harburg, Germany.
• 1992-2008 Special research worker at the Academy of Finland and Helsinki University of Technology, Finland.
• 2006 - Leading Research Scientist at the Institute of Solid State Physics, University of Latvia, Riga, Latvia.

Honours and Awards

• Foreign Member, Latvian Academy of Sciences, 2001
• Full Member, Latvian Academy of Sciences, 2009

Scientific Visits

• 1999- 2000 (twelve months) guest scientist at the Research Centre Karlsruhe, Germany.
• 2002 (three months) guest professor at Fukui University, Japan.
• 2003 (four months) guest professor at Fukui University, Japan.
• 2004 (four month) guest scientist at the Research Centre Karlsruhe, Germany.
• 2005 (three months) guest professor at Fukui University, Japan.
• 2006 (three months) guest professor at Fukui University, Japan.
• 2007 (three months) guest professor at Fukui University, Japan.
• 2010 (three months) guest professor at Fukui University, Japan.
• 2012 (three months) guest professor at Fukui University, Japan.

International expertise

• Member of the International Coordinating Committee for the Development Program for the Electron Cyclotron Wave Systems for the International Thermonuclear Experimental Reactor
• Member of the Experts Group of the Fusion Program of the European Commission
• INTAS Project “Frequency tunable microwave sources for plasma applications” (coordinator)
• INTAS Project “Development and investigation of novel methods by gyrotron efficiency enhancement by means of improved quality of the helical electron beam,” (participant)
• Member of the European Plasma Physics Theory Committee
• Latvia’s representative at Euratom STAC
• Life member of the American Physical Society
• Senior member of IEEE
• Organiser of the 13th European Fusion Theory Conference to be held on 12-15 October 2009, Riga, Latvia

• In 2005 obtained a 24 months EURATOM fellowship for research topic „ Stochastization of magnetic field lines and magnetic reconnection.”
• In 2008 obtained a grant for the European project F4E-2008-GRT-08 “Development of the European Gyrotron.”

1. O. Dumbrajs and A. Möbius. "Verfahren zur Erhöhung und/oder Sicherstellung des Wirkungsgrades eines Gyrotrons und Gyrotron zur Durchführung des Verfahrens."
   Patentanmeldung 4236149.4, Anmeldetag: 27.10.92. Deutsches Patentamt, München, 27. Oktober 1995.
2. O. Dumbrajs, A. Möbius, and M. Mühleisen . “Ein in der Frequenz einstellbares Gyrotron.”
   Patentanmeldung 19532785, Anmeldetag: 06.09.95. Deutsches Patentamt, München, 17. April 1997.
3. Dumbrajs. “Innenleiter eines koaxialen Gyrotrons mit um den Umfang gleichverteilten axialen Korrugationen.”
   Patentanmeldung 10040320.4, Anmeldetag: 17.08.2000. Deutsches Patentamt, München, 28. Mai 2001.

• In 1967 I worked for 8 months as an assistant at the University of Latvia. During this period I lectured at undergraduate level, giving courses on "Electrodynamics", "Thermodynamics", and "Classical Field Theory”
• During my work at the Helsinki University of Technology (1993- 2005) I gave lectures on “Nuclear Physics” and “Introduction into Nonlinear Dynamics and Chaos”.
• I have supervised many BC and PhD theses in the fields “Generation of Millimeter Waves” and “Stellarator and tokamak physics.”

O. Dumbrajs "Review of the mode competition in gyrotrons developed in Russia."
Chapter in "Gyrotron Oscillators: Their Principles and Practice.”
Editor C.J. Edgcombe, 1993, Taylor&Francis.

• O. Dumbrajs. "Strong interaction and numerical analytic continuation."
  Sov. J. Part. Nucl. 6, 132 (1973).
• S. Dubnicka and O. Dumbrajs. "Analyticity in hadron-nuclei binary reactions."
  Phys. Reports 19C, 141 (1975).
• O. Dumbrajs and M. Staszel. "Forward dispersion relations: two decades of life."
  Postepy Fizyki 27, 253 (1976).
• O. Dumbrajs. "Inverse problem in nuclear and particle physics."
  Postepy Fizyki 28, 417 (1977).
• O. Dumbrajs, R. Koch, G. Oades, H. Behrens, J.J. De Swart, and P. Kroll. "Compilation of coupling constants and low-energy scattering parameters."
  Nucl. Phys. B216, 277 (1983).
• M.I. Airila and O. Dumbrajs. “Stochastic processes in gyrotrons.”
  Nuclear Fusion 43, 1446 (2003).
• O. Dumbrajs and G.S. Nusinovich. “Coaxial gyrotrons: past, present and future.”
  IEEE Transactions on Plasma Science, 32, 934 (2004).

Papers: more than 190 refereed papers and more than 110 reports in proceedings of international scientific conferences.

Main (recent) papers

1. O. Dumbrajs, V. Igochine, D. Constantinescu, H. Zohm, and ASDEX Upgrade team. „Stochastization as a possible cause of fast reconnection in the frequently interrupted regime of neoclassical tearing modes.“ Phys. Plasmas 12, 110704 (2005).
2. V. Igochine, O. Dumbrajs, D. Constantinescu, H. Zohm, G. Zvejnieks. “Stochastization as a possible cause for fast reconnection during MHD mode activity in the ASDEX Upgrade tokamak.” Nuclear Fusion 46, 741 (2006).
3. O. Dumbrajs, V. Igochine, and H. Zohm. "Diffusion in a stochastic magnetic field in ASDEX Upgrade." Nucl. Fusion 48, 024011 (2008).
4. D. Constantinescu, O. Dumbrajs, V. Igochine, and B. Weyssow. "On the accuracy of some mapping techniques used to study the magnetic field dynamics in tokamaks." Nucl. Fusion 48, 024017 (2008).
5. O. Dumbrajs and T. Idehara. "Hysteresis in mode competition in high power 170 GHz gyrotron for ITER." Int. J. Infrared Millimeter Waves 29, 232 (2008).
6. O. Dumbrajs, Y. Kominis and G.S. Nusinovich.“Electron dynamics in the process of mode switching in gyrotrons.” Physics of Plasmas 16, 013102 (2009).
7. O. Dumbrajs, V. Igochine, A. Gude, M. Maraschek, and H. Zohm. “Temporal evolution of neoclassical tearing modes in the frequently interrupted regime.” Physics of Plasmas 17, 053104 (2010).
8. O. Dumbrajs and G.S. Nusinovich. „To the theory of high-power gyrotrons with uptapered resonators.” Phys. Plasmas 17, 053104 (2010).
9. O. Dumbrajs.„Influence of possible reflections on the operation of European ITER gyrotrons”J. Infrared Milli.Terahz. Waves 31, 892 (2010).
10. O. Dumbrajs, T. Idehara, and S.Sabchevski.“Design of an optimized resonant cavity for a compact sub-Terahertz gyrotron” J.Infrared Milli. Terahz. Waves 31, 1115 (2010.
11. O. Dumbrajs, and T. Idehara.“Frequency tunable gyrotron FU CW VA for measuring hyperfine split of positronium” J.Infrared Milli. Terahz. Waves 31,1265 (2010).
12. V. Igochine, J. Boom, I. Classen, O.Dumbrajs, K. Lackner, G. Pereverzev, H.Zohm and ASDEX-U team.“Structure and dynamics of sawteeth crashes in ASDEX Upgrade” Phys. Plasmas 17, 122506 (2010).
13. D. Constantinescu, O. Dumbrajs, V. Igochine, K. Lackner, R. Meyer-Spasche and H. Zohm.“ A low-dimensional model system for quasi-periodic plasma perturbations”Phys. Plasmas 18, 062307 (2011).
14. Erzhong Li, Liqun Hu, V. Igochine, O. Dumbrajs, and Kaiyun Chen.“Understanding complex magnetohydrodynamic activities associated with a relaxation in HT-7 tokamak”Plasma Phys. Control.Fusion 53,085019 (2011).

 

Citations: more than 1900

Hirsh-index: 19

Journal	IF2006	Number of papers
Acta Phys. Pol. B	0.882	3
Ann. Phys.	3.019	1
Czech. J. Phys.	0.568	1
Fortschr. der Physik	2.007	3
Fusion Engin. Design	0.598	1
IEEE Tr. Electron Devices	2.052	1
IEEE Tr. Plasma Science	1.144	23
Int. J. Electronics	0.459	14
Int. J. Infrared Mill. Waves	0.755	12
J. Appl. Phys.	2.316	1
J. Comm. Tech. Electronics	0.102	2
J. Exp. Theor. Phys.	0.937	4
J. Part. Nucl.	0.393	1
J. Phys. B	2.024	2
J. Phys. G	1.781	5
Nuovo Cimento B	0.351	6
Nuclear Fusion	3.278	8
Nuclear Physics A	2.155	5
Nuclear Physics B	5.199	15
Phys. Lett. B	5.043	4
Phys. Plasmas	2.258	17
Physics Reports	10.438	1
Phys. Rev. A	3.047	2
Phys. Rev. C	3.327	5
Phys. Rev. D	4.896	1
Phys. Rev. E	2.438	1
Phys. Scripta	1.161	1
Plasma Phys. Control. Fusion	2.820	4
Rev. Scien. Instr.	1.541	2
Teor. Mat. Fiz.	0.626	2
Z. Naturforschung A	0.904	9

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Last update 8.06.2012