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D. Wagner,
J. Stober,
S. Baumel, T. Franke,
F. Leuterer,
E. Poli,
F. Monaco,
M. Munich,
H. Schutz,
H. Zohm, [......],
H. Hohnle,
A.G. Litvak,
G.G. Denisov,
A. Cirkov,
L.G. Popov,
V.O. Nichiporenko,
V.E. Myasnikov,
E.M. Tai,
E.A. Solyanova,
S.A. Malygin
[show abstract]
[hide abstract]
ABSTRACT: A new ECRH system is currently under construction at the ASDEX Upgrade tokamak. It employs for the first time depressed collector gyrotrons, step-tunable in the range 105-140 GHz. In its final stage it will consist of 4 gyrotrons with a total output power of 4 MW and a pulse length of 10 s. In this paper we describe recent extensions of the system and some experimental results.
Infrared, Millimeter, and Terahertz Waves, 2009. IRMMW-THz 2009. 34th International Conference on; 10/2009
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D.H. Wagner,
J.K. Stober,
F. Leuterer,
G. Sips,
G. Grunwald,
F. Monaco,
M.J. Munich,
E. Poli,
H. Schutz,
F. Volpe, [......],
C. Lechte,
A.G. Litvak,
G.G. Denisov,
A. Chirkov,
E. Tai,
L. Popov,
V. Nichiporenko,
V. Myasnikov,
E. Solyanova,
S. Malygin
[show abstract]
[hide abstract]
ABSTRACT: A multifrequency electron cyclotron resonance heating (ECRH) system is currently under construction at the ASDEX Upgrade tokamak experiment. The system employs depressed collector gyrotrons, step tunable in the range of 105-140 GHz, with a maximum output power of 1 MW and a pulse length of 10 s. One two-frequency GYCOM gyrotron has been in routine operation at ASDEX Upgrade since 2006. A further extension of the system with three more gyrotrons is underway. An in situ calibration scheme for the broadband torus window has been developed. The system is equipped with fast steerable mirrors for real-time MHD control. The gyrotron and the mirrors are fully integrated into the discharge control system. The ECRH system turned out to be essential for the operation of H-modes after covering the plasma facing components of ASDEX Upgrade with tungsten. Deposition of ECRH inside rho<sub>tor</sub> < 0.2 is necessary to prevent accumulation of W in plasmas with high pedestal temperatures. With respect to the limited loop voltage available in ITER, the use of ECRH for neutral-gas preionization to facilitate plasma breakdown and its application during the current ramp-up to increase the conductivity in order to save transformer flux have been demonstrated successfully for 105 GHz, 3.2 T (O1-mode) and 140 GHz, 2.2 T (X2-mode), corresponding to 170 GHz at ITER with the full and half values of its foreseen toroidal field of 5.3 T.
IEEE Transactions on Plasma Science 04/2009; · 1.17 Impact Factor
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D. Wagner, T. Franke,
F. Leuterer,
F. Monaco,
M. Munich,
H. Schutz,
J. Stober,
F. Volpe,
H. Zohm,
M. Thumm, [......],
C. Lechte,
A.G. Litvak,
G.G. Denisov,
A. Cirkov,
E.M. Tai,
L.G. Popov,
V.O. Nichiporenko,
V.E. Myasnikov,
E.A. Solyanova,
S.A. Malygin
[show abstract]
[hide abstract]
ABSTRACT: Currently, a new multi-frequency ECRH system is under construction at the ASDEX Upgrade Tokamak experiment. This system employs, for the first time in a fusion device, multi-frequency gyrotrons, step-tunable in the range 105-140 GHz. The system includes fast steerable launchers at the front end that will allow for very localized feedback controlled power deposition in the plasma.
Infrared, Millimeter and Terahertz Waves, 2008. IRMMW-THz 2008. 33rd International Conference on; 10/2008
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D Wagner,
G. Grunwald,
F. Leuterer,
F. Monaco,
M. Munich,
H. Schultz,
J. Stober,
H. Zohm, T. Franke,
M. Thumm, [......],
C. Lechte,
A.G. Litvak,
A.V. Cirkov,
G.G. Denisov,
L. G. Popov,
V. O. Nichiporenko,
V.E. Myasnikov,
E.M. Tai,
E. A. Solyanova,
S. A. Malygin
[show abstract]
[hide abstract]
ABSTRACT: Summary form only given. A multi-frequency ECRH system is currently under construction at the ASDEX Upgrade tokamak experiment. The system employs depressed collector gyrotrons, step-tunable in the range 105-140 GHz, with a maximum output power of 1 MW and a pulse length of 10 s. One two-frequency GYCOM gyrotron is in routine operation at ASDEX Upgrade since 2006. A further extension of the system with 3 more gyrotrons is underway. These gyrotrons will be step-tunable and operate at two additional intermediate frequencies between 105 and 140 GHz. They will be equipped with broadband Brewster windows. Since the transmission of the power from the gyrotron to the tokamak is in normal air, a second broadband vacuum window is required at the tokamak vacuum barrier. These windows must be broadband also for elliptically polarized beams. Therefore tunable double disc CVD diamond windows will be installed at the torus. To condition and test the gyrotrons a new long-pulse dummy load, capable of 1 MW, 10 s and operation in normal air has been operated very reliably. One of the main applications of the new ECRH system will be the suppression of neoclassical tearing modes (NTM). For this reason fast-steerable mirrors have been installed. This capability will allow feedback control of the deposition on the time scale of NTM growth, providing the possibility to validate this scheme for ITER in ASDEX Upgrade. For NTM stabilization experiments a fast modulation capability of the gyrotrons is required and was tested. This is especially important for future experiments like ITER where the width of the driven EC current will be larger than the marginal island size of the NTM leading to a loss of current drive efficiency in the non-modulated case.
Plasma Science, 2008. ICOPS 2008. IEEE 35th International Conference on; 07/2008
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D.H. Wagner,
G. Grunwald,
F. Leuterer,
A. Manini,
F. Monaco,
M.J. Munich,
H. Schutz,
J. Stober,
H. Zohm, T. Franke, [......],
G.G. Denisov,
A.V. Chirkov,
E.M. Tai,
L.G. Popov,
V.O. Nichiporenko,
V.E. Myasnikov,
E.A. Solyanova,
S.A. Malygin,
F. Meo,
P.P. Woskov
[show abstract]
[hide abstract]
ABSTRACT: A new multifrequency electron cyclotron resonance heating system is under construction for the Axially Symmetric Divertor Experiment (ASDEX) Upgrade tokamak experiment. For the first time in a fusion device, this system employs multifrequency gyrotrons that are step-tunable in the range 105-140 GHz. In its final stage the system will consist of four gyrotrons with a total power of 4 MW and a pulselength of 10 s. The first two gyrotrons, working at 105 and 140 GHz, were installed and tested. Transmission line elements such as corrugated waveguides, polarizer mirrors and vacuum windows are designed to cope with this frequency band. The system includes fast steerable launchers at the front end that will allow for localized feedback-controlled power deposition in the plasma.
IEEE Transactions on Plasma Science 05/2008; · 1.17 Impact Factor
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D. Wagner,
G. Grünwald,
F. Leuterer,
A. Manini,
F. Monaco,
M. Münich,
H. Schütz,
J. Stober,
H. Zohm, T. Franke, [......],
G.G. Denisov,
A.V. Chirkov,
E.M. Tai,
L.G. Popov,
V.O. Nichiporenko,
V.E. Myasnikov,
E.A. Solyanova,
S.A. Malygin,
F. Meo,
P. Woskov
[show abstract]
[hide abstract]
ABSTRACT: Currently, a new multi-frequency ECRH system is under construction at the ASDEX Upgrade tokamak experiment. This system employs, for the first time in a fusion device, multi-frequency gyrotrons, step-tunable in the range 105–140 GHz. The first two gyrotrons, working at 105 and 140 GHz, were installed and tested. The matching optics unit includes a set of phase correcting mirrors for each frequency as well as a pair of broadband polarizer mirrors. The transmission line consists of non-evacuated corrugated HE11 waveguides with an inner diameter (ID) of 87 mm and has a total length of about 70 m. Transmission losses were deducted from calorimetric measurements both at the beginning and at the end of the transmission line at both frequencies and are in reasonable agreement with theory. Two transmission lines are completed so far and first plasma experiments with the new system have started. The first gyrotron Odissey-1 is currently being equipped with a broadband chemical vapour deposition (CVD) diamond Brewster output window and will become a step-tunable gyrotron with the additional frequencies 117 and 127 GHz. A tunable double-disc CVD-diamond window will be mounted at the torus. The system includes fast steerable launchers at the front end that will allow very localized feedback controlled power deposition in the plasma.
Nuclear Fusion 04/2008; 48(5):054006. · 4.09 Impact Factor
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D. Wagner,
F. Leuterer,
A. Martini,
F. Monaco,
M. Munich,
H. Schutz,
J. Stober,
H. Zohm, T. Franke,
M. Thumm, [......],
W. Kasparek,
C. Lechte,
A.G. Litvak,
G.G. Denisov,
E.M. Tai,
L.G. Popov,
V.O. Nichiporenko,
V.E. Myasnikov,
E.A. Solyanova,
S. Malygin
[show abstract]
[hide abstract]
ABSTRACT: The power deposition in the plasma is primarily determined by the magnetic field B(r). For a single frequency ECRH system this has the consequence that for central heating the magnetic field is no longer a free parameter. However, for plasmas with different plasma currents or different equilibria, the magnetic field should be a free parameter in order to operate at a reasonable edge safety factor q(a). Furthermore, in a plasma with given parameters, some experimental features, like suppression of neoclassical tearing modes (NTM), require to drive current on the high field side without changing the magnetic field. These requests can be satisfied if the gyrotron frequency is variable . In the experiments performed up to now in ASDEX Upgrade, the installed power was only 2 MW, of which 1.6 MW was coupled to the plasma. This imposes a limit for current drive, NTM stabilization or generation of internal transport barriers . The requirement for the new ECRH system is therefore an installed power of 4 MW. Since the current diffusion time in hot plasmas, like those with an internal transport barrier and Te > 10 keV, is several seconds, we need a pulse duration of 10 s compatible with the limit of ASDEX Upgrade flat top discharges. A further requirement is the capability for very localized power deposition such that its center can be feedback controlled, for instance to keep it on a resonant q-surface. For this purpose fast movable mirrors have been installed.
Infrared and Millimeter Waves, 2007 and the 2007 15th International Conference on Terahertz Electronics. IRMMW-THz. Joint 32nd International Conference on; 10/2007
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F. Leuterer,
D. Wagner,
A. Manini,
F. Monaco,
M. Munich,
F. Ryter,
H. Schutz,
H. Zohm, T. Franke,
M. Thumm, [......],
G. Gantenbein,
W. Kasparek,
A.G. Litvak,
L.G. Popov,
V.O. Nichiporenko,
V.E. Myasnikov,
G.G. Denisov,
E.M. Tai,
E.A. Solyanova,
S.A. Malygin
[show abstract]
[hide abstract]
ABSTRACT: Summary form only given. The power deposition in ECRH (electron cyclotron resonance heating) of fusion plasmas is primarily determined by the magnetic field. For a single frequency ECRH system this has the consequence that for central heating the magnetic field is no longer a free parameter. However, for tokamak plasmas with different plasma currents or different equilibria, the magnetic field should be a free parameter in order to operate at a reasonable edge safety factor q(a). Furthermore, in a plasma with given parameters, some experimental features, like suppression of neoclassical tearing modes (NTM), require to drive current on the high field side without changing the magnetic field. These requests can be satisfied if the gyrotron frequency is variable. A new broadband ECRH system is currently under construction at the ASDEX Upgrade tokamak at IPP Garching. This system will employ multi-frequency gyrotrons which are step-tunable in the frequency range 105-140 GHz. In its final stage the system will consist of 4 gyrotrons with a total power of 4 MW and a pulse length of 10 s. It employs a fast steerable launcher in the plasma vessel for feedback controlled power deposition that allows for poloidal steering of 10 deg, within 100 ms. Transmission line elements, such as corrugated waveguides, polarizer mirrors and vacuum windows, are designed to cope for this frequency band. The first two-frequency gyrotron, operating at 105 GHz and 140 GHz, is currently being put into operation at ASDEX Upgrade
Plasma Science, 2006. ICOPS 2006. IEEE Conference Record - Abstracts. The 33rd IEEE International Conference on; 07/2006
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D. Wagner,
F. Leuterer,
A. Manini,
F. Monaco,
M. Münich,
F. Ryter,
H. Schütz,
H. Zohm, T. Franke,
R. Heidinger, [......],
W. Kasparek,
G. Gantenbein,
A. G. Litvak,
L. G. Popov,
V. O. Nichiporenko,
V. E. Myasnikov,
G. G. Denisov,
E. M. Tai,
E. A. Solyanova,
S. A. Malygin
[show abstract]
[hide abstract]
ABSTRACT: A new broadband ECRH (Electron Cyclotron Resonance Heating) system is currently under construction at the ASDEX Upgrade tokamak. This system will employ multi-frequency gyrotrons
step-tunable in the range 105–140 GHz. In its final stage the system will consist of 4 gyrotrons with a total power of 4 MW
and a pulse length of 10 s. It employs a fast steerable launcher for feedback controlled deposition that allows for poloidal
steering of 10° within 100 ms. Transmission line elements, such as corrugated waveguides, polarizer mirrors and vacuum windows,
are designed to cope for this frequency band.
International Journal of Infrared and Millimeter Waves 01/2006; 27(2):173-182. · 0.58 Impact Factor
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D. Wagner,
G. Grunwald,
F. Leuterer,
A. Manini,
F. Monaco,
M. Munich,
F. Ryter,
H. Schutz,
H. Zohm, T. Franke,
R. Heidinger,
K. Koppenburg,
M. Thumm,
W. Kasparek,
G. Gantenbein,
G.G. Denisov,
A. Litvak,
V. Zapevalov
[show abstract]
[hide abstract]
ABSTRACT: The first two-frequency gyrotron has been installed in the new multi-frequency ECRH system at the ASDEX Upgrade Tokamak experiment. In its final stage the system consist of 4 gyrotrons, tunable in the range 105-140 GHz with a total power of 4 MW and a pulse length of 10 s. It employs a fast steerable launcher for feedback controlled deposition that allows for poloidal steering of 10° within 100 ms. Transmission line elements, such as corrugated waveguides, polarizer mirrors and vacuum windows, are designed to cope for this frequency band.
Infrared and Millimeter Waves and 13th International Conference on Terahertz Electronics, 2005. IRMMW-THz 2005. The Joint 30th International Conference on; 10/2005
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F. Leuterer,
G. Grunwald,
F. Monaco,
M. Munich,
F. Ryter,
H. Schutz,
D. Wagner,
H. Zohm, T. Franke,
G. Dammertz,
H. Heidinger,
K. Koppenburg,
M. Thumm,
W. Kasparek,
G. Gantenbein,
G.G. Denisov,
A. Litvak,
V. Zapevalov
[show abstract]
[hide abstract]
ABSTRACT: A multi-frequency ECRH system with 4 gyrotrons, tunable in the range of 105-140 GHz, is currently under construction at ASDEX Upgrade with a total power of 4 MW and a pulse length of 10 s. A fast steerable launcher for feedback controlled deposition has been installed that allows for poloidal steering of 10° within 100 ms. Transmission line elements, such as corrugated waveguides, polarizer mirrors and vacuum windows, are designed to cope for this frequency band.
Infrared and Millimeter Waves, 2004 and 12th International Conference on Terahertz Electronics, 2004. Conference Digest of the 2004 Joint 29th International Conference on;
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D Wagner,
J. Stober,
F. Leuterer,
G. Sips,
G. Grünwald,
F. Monaco,
M. Münich,
E. Poli,
H. Schütz,
F. Volpe, [......],
C. Lechte,
A.G. Litvak,
G.G. Denisov,
A. Chirkov,
E. Tai,
L. G. Popov,
V. O. Nichiporenko,
V.E. Myasnikov,
E. A. Solyanova,
S. A. Malygin
Litvak, A. G.: Strong Microwaves: Sources and Applications. Proceedings of the 7th International Workshop, Russian Academy of Sciences, 304-311 (2009).
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D Wagner,
J. Stober, T. Franke,
F. Leuuterer,
E. Poli,
F. Monaco,
M. Münich,
H. Schütz,
H. Zohm,
M. Thumm, [......],
H. Höhnle,
A.G. Litvak,
G.G. Denisov,
A. Cirkov,
L. G. Popov,
V. O. Nichiporenko,
V.E. Myasnikov,
E.M. Tai,
E. A. Solyanova,
S. A. Malygin
Proceedings of the 34th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz 2009), IEEE (2009).
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F. Leuterer,
K. Kirov,
F. Monaco,
M. Münich,
H. Schütz,
F. Ryter,
D. Wagner,
R. Wilhelm,
H. Zohm, T. Franke, [......],
W. Kasparek,
G.A. Müller,
A. Bogdashov,
G. Denisov,
V. Kurbatov,
A. Kuftin,
A. Litvak,
S. Malygin,
E. Tai,
V. Zapevalov
[show abstract]
[hide abstract]
ABSTRACT: A new ECRH system is being constructed for ASDEX Upgrade with a total power of 4 MW, generated by four gyrotrons, and a pulse duration of 10 s. Particular features are the use of gyrotrons which can work at various frequencies in the range 104–140 GHz and correspondingly broad band transmission components. The transmission will be at normal air pressure, and at the torus we will have a tunable double disk vacuum window. A further aim is the installation of fast moveable mirrors for a feedback controlled localized power deposition.
Fusion Engineering and Design.
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D Wagner,
J. Stober,
S. Bäumel, T. Franke,
F. Leuterer,
F. Monaco,
M. Münich,
D. Schmid-Lorch,
H. Schütz,
H. Zohm, [......],
C. Lechte,
A.G. Litvak,
G.G. Denisov,
A. Cirkov,
E.M. Tai,
L. G. Popov,
V. O. Nichiporenko,
V.E. Myasnikov,
E. A. Solyanova,
S. A. Malygin
-
F. Leuterer,
K. Kirov,
F. Monaco,
M. Münich,
H. Schütz,
F. Ryter,
D Wagner,
R. Wilhelm,
H. Zohm, T. Franke, [......],
M. Thumm,
X Yang,
W. Kasparek,
G. Gantenbein,
H. Hailer,
G. A. Müller,
K. Schwörer,
G.G. Denisov,
A. Litvak,
V. Zapevalov
-
F. Leuterer,
K. Kirov,
F. Monaco,
M. Münich,
H. Schütz,
F. Ryter,
D Wagner,
R. Wilhelm,
H. Zohm, T. Franke, [......],
M. Thumm,
X Yang,
W. Kasparek,
G. Gantenbein,
H. Hailer,
G. A. Müller,
K. Schwörer,
G.G. Denisov,
A. Litvak,
V. Zapevalov
-
F. Leuterer,
G. Grünwald,
F. Monaco,
M. Münich,
H. Schütz,
F. Ryter,
D. Wagner,
H. Zohm, T. Franke,
G. Dammertz,
R. Heidinger,
K. Koppenburg,
M. Thumm,
W. Kasparek,
G. Gantenbein,
H. Hailer,
G.G. Denisov,
A. Litvak,
V. Zapevalov
[show abstract]
[hide abstract]
ABSTRACT: A new ECRH system is currently being constructed at ASDEX Upgrade with a total power of 4 MW and pulse length of 10 s. The power will be generated by four gyrotrons which can work either at two frequencies (2f-gyrotron), 105 or 140 GHz, or step-tunable at many frequencies within this range (mf-gyrotron). The transmission line and its components are especially designed to cope with the wide frequency range. A fast poloidal mirror steering will be used for feedback controlled power deposition, particularly in experiments on suppression of neoclassical tearing modes.
Fusion Engineering and Design.
