The ECRH-Power Upgrade at the Wendelstein 7-X Stellarator

Laqua, H. P.; Avramidis, K.A.; Braune, H.; Chelis, Ioannis; Gantenbein, G.; Illy, S.; Ioannidis, Zisis C.; Jelonnek, J.; Jin, Jianbo; Krier, L.; Lechte, C.; Leggieri, Alberto; Legrand, François; Marsen, S.; Moseev, D.; Oosterbeek, H.; Rzesnicki, T.; Ruess, Tobias; Stange, T.; Thumm, M.; Tigelis, I. G.; Wolf, R. C.

doi:10.1051/epjconf/202327704003

Cited by 7 publications

(1 citation statement)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The key heating system is the Electron Cyclotron Resonance Heating (ECRH) system, consisting of 10 gyrotrons with power per gyrotron ranging from 0.6 MW up to 1.0 MW at 140 GHz. A phased upgrade of the installation is in progress with the addition of 2 gyrotrons and the development of 1.5 MW and 2.0 MW gyrotrons, such that at the end of the upgrade 4 gyrotrons will be available in each power class of 1.0, 1.5 and 2.0 MW [2]. The increased ECRH power, combined with O2 and X3 heating schemes at high densities, will lead to increased microwave stray radiation.…”

mentioning

confidence: 99%

MISTRAL campaign in support of W7-X long pulse operation

Oosterbeek

Stern²,

Braune³

et al. 2023

EPJ Web Conf.

View full text Add to dashboard Cite

Following two initial campaigns [1], Stellarator Wendelstein 7-X (W7-X) has now completed the construction phase by installation of active cooling of all plasma facing components. The machine is presently commissioned for the next campaign (OP2) aiming at 1 GJ per pulse, e.g. 100 s at 10 MW, eventually aiming at 18 GJ, e.g. 1800 s at 10 MW. The key heating system is the Electron Cyclotron Resonance Heating (ECRH) system, consisting of 10 gyrotrons with power per gyrotron ranging from 0.6 MW up to 1.0 MW at 140 GHz. A phased upgrade of the installation is in progress with the addition of 2 gyrotrons and the development of 1.5 MW and 2.0 MW gyrotrons, such that at the end of the upgrade 4 gyrotrons will be available in each power class of 1.0, 1.5 and 2.0 MW [2]. The increased ECRH power, combined with O2 and X3 heating schemes at high densities, will lead to increased microwave stray radiation. This is non-absorbed microwave power that diffuses inside the vessel and is incident on all in-vessel components including vacuum windows and attached diagnostic systems. A fraction of the stray radiation is absorbed by resistive or dielectric losses of these components, leading to thermal loads that scale with stray radiation levels and pulse length. At W7-X a high power microwave stray radiation launch facility ’MISTRAL’ is available that is used to qualify invessel components for use at specified microwave surface power densities [Wm−2]. This paper reports on MISTRAL campaigns in 2020 2021 for testing of stray radiation loads during OP2 in W7-X, as well as on an EUROfusion program assessing stray radiation loads on ITER components. A dedicated, absolutely calibrated, caloric load was developed for the campaign to obtain measurement of stray radiation power levels as well as to conveniently expose samples. Amongst other we report on shielding concepts using metal enclosures combined with microwave absorbing coatings and dielectric heating of vacuum windows.

show abstract

mentioning

confidence: 99%

MISTRAL campaign in support of W7-X long pulse operation

Oosterbeek

Stern²,

Braune³

et al. 2023

EPJ Web Conf.

View full text Add to dashboard Cite

show abstract

High power mm-wave loss measurements of ITER ex-vessel waveguide components at the FALCON test facility at the Swiss Plasma Center

Goodman

Torreblanca²,

Borderas³

et al. 2023

EPJ Web Conf.

View full text Add to dashboard Cite

Many future fusion devices will rely heavily, if not solely, on electron cyclotron (EC) heating subsystems to provide bulk heating, instability control (neoclassical tearing mode (NTM) stabilization), and thermal instability control. Efficient use of the installed heating power (gyrotrons) requires low-loss transmission of the power over 100s of meters since the mm-wave sources need to be installed where the stray magnetic field has a small amplitude. Transmission lines are used to propagate the mm-wave power over this long distance. Quasi-optical techniques (mirrors) are used at W7X and are planned for DTT, for example. Guided components are installed at DIII-D, TCV and elsewhere and are planned at JT60SA and ITER. High power test facilities exist to evaluate the power transmission of assemblies of guided components (transmission lines). The European test facility FALCON was setup by Switzerland and Fusion for Energy (F4E) in Lausanne Switzerland at the Swiss Plasma Center (SPC) in the Ecole Polytechnique Fédérale de Lausanne (EPFL). Operations are funded through a framework contract with F4E. SPC operates the facility. Two ITER-class 170GHz gyrotrons are housed within the facility and used to evaluate the thermal behaviour of components provided by various ITER partners. Loss measurements are presented for miter bends and waveguides of several materials at two different diameters. The results are used to model the expected losses in the ITER ex-vessel waveguides (EW) of all five EC launchers.

show abstract

Development of the 174 GHz collective Thomson scattering diagnostics at Wendelstein 7-X

Ponomarenko,

Moseev,

Stange

et al. 2024

Review of Scientific Instruments

View full text Add to dashboard Cite

In this paper, we present the design and commissioning results of the upgraded collective Thomson scattering diagnostic at the Wendelstein 7-X stellarator. The diagnostic has a new radiometer designed to operate between the second and third harmonics of the electron cyclotron emission from the plasma at 171–177 GHz, where the emission background has a minimum and is of order 10–100 eV. It allows us to receive the scattered electromagnetic field with a significantly improved signal-to-noise ratio and extends the set of possible scattering geometries compared to the case of the original instrument operated at 140 GHz. The elements of the diagnostic are a narrowband notch filter and a frequency stabilized probing gyrotron that will allow measuring scattered radiation spectra very close to the probing frequency. Here, we characterize the microwave components applied to the radiometer and demonstrate the performance of the complete system that was achieved during the latest experimental campaign, OP2.1.

show abstract

The ECRH-Power Upgrade at the Wendelstein 7-X Stellarator

Cited by 7 publications

References 7 publications

MISTRAL campaign in support of W7-X long pulse operation

MISTRAL campaign in support of W7-X long pulse operation

High power mm-wave loss measurements of ITER ex-vessel waveguide components at the FALCON test facility at the Swiss Plasma Center

Development of the 174 GHz collective Thomson scattering diagnostics at Wendelstein 7-X

Contact Info

Product

Resources

About