Design of a dual high-power, long pulse, steerable ECH launcher for DIII-D

Ellis, R.; Hosea, J.; Wilson, J. R.; Prater, R.; Callis, R.W.

doi:10.1063/1.1424200

Cited by 10 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The four fully articulating dual launchers [3] [ Fig. 5(a)] can steer the RF beams poloidally and toroidally ±20°in each direction.…”

Section: Ech Launchersmentioning

confidence: 99%

“…The four dual launchers installed on DIII-D [3] inject the RF power from the tokamak's low-field side. A movable mirror allows the launched RF to be directed over ±20°t oroidally to create both co-and counter-current drive, or scanned poloidally over 40°in the tokamak so it can be absorbed at the second-harmonic resonance on nearly all flux surfaces.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Performance and Upgrades for the Electron Cyclotron Heating System on DIII-D

Cengher

Lohr

Gorelov

et al. 2014

IEEE Trans. Plasma Sci.

Self Cite

View full text Add to dashboard Cite

The electron cyclotron heating (ECH) system on the DIII-D fusion reactor consists of six 110-GHz gyrotrons with 6 MW installed power for pulses limited administratively to 5 s in length. The transmission coefficient is better than −1.1 dB for four of the transmission lines, which is close to the theoretical value. A new depressed collector gyrotron was recently installed and is injecting up to 720 kW of power into DIII-D during 2013 tokamak operations. Three of the four dual waveguide launchers, which can steer the RF beams ±20°both poloidally and toroidally, were used for real-time neoclassical tearing mode control and suppression with increased poloidal scanning speed up to 60°/s and positioning accuracy of the beams of ±2 mm at the plasma center. The ECH capabilities on DIII-D are being steadily updated, leading to increased experimental flexibility and high reliability of the system. In the past year, the ECH system reliability reached 87% for 2352 successful individual gyrotron shots into DIII-D. Planning is under way for the addition of two new depressed collector gyrotrons, one at 110 GHz, 1.2 MW and another at 117.5 GHz, 1.5 MW generated power, both of which are in the test stage at Communications and Power Industries.

show abstract

“…The four fully articulating dual launchers [3] [ Fig. 5(a)] can steer the RF beams poloidally and toroidally ±20°in each direction.…”

Section: Ech Launchersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Performance and Upgrades for the Electron Cyclotron Heating System on DIII-D

Cengher

Lohr

Gorelov

et al. 2014

IEEE Trans. Plasma Sci.

Self Cite

View full text Add to dashboard Cite

show abstract

New Frequency Step-Tunable Ecrh System for Asdex Upgrade

Wágner

Leuterer

Manini

et al. 2006

Int J Infrared Milli Waves

View full text Add to dashboard Cite

Status of the new ECRH system for ASDEX Upgrade

Leuterer

Grunwald

Monaco

et al. 2005

Fusion Engineering and Design

View full text Add to dashboard Cite

The new ECRH system which is currently under construction at ASDEX Upgrade is aimed for a total power of 4 MW, generated by 4 gyrotrons, at a pulse length of 10 sec. A particular feature is the use of multifrequency gyrotrons, where the gyrotrons will work either at two frequencies (105/140 GHz) or will be step-tunable in the range 105-140 GHz. The system should allow for central heating at different magnetic fields. It will also give more flexibility for the stabilization of neoclassical tearing modes (NTM) through the possibility of current drive on the high field side without changing the magnetic field and very localized feedback controlled power deposition with a narrow beamwidth by using a fast steerable launcher. The transmission line components are especially designed to cope for the large bandwidth of the system. RequirementsThe power deposition in the plasma 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 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 program points, like suppression of neoclassical tearing modes, 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 available power was only 2 MW, of which 1.6 MW is injected into the plasma. This imposed a real limit for current drive, NTM stabilization or generation of internal transport barriers [1]. The requirement for the new 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 require a pulse duration of 10 sec compatible with the limit of 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 we will install fast moveable mirrors. GyrotronsThe system will be constructed in several steps. The first gyrotron to be installed can work at 105 GHz and at 140 GHz. The corresponding operating modes are TE 17,6 and TE 22,8 (two-frequency gyrotron). Here we make use of the 3λ/2 and 4λ/2 resonances (λ is the wavelength) of the single disk synthetic diamond vacuum window at these frequencies. A second gyrotron will be steptunable, i.e. it can work at several frequencies within the same frequency range. For each frequency the gyrotron oscillates in a different cavity mode. Fig. 1 shows the possible modes and frequencies. Short pulse test gyrotrons have demonstrated efficient generation of power in excess of 1 MW at all these frequencies [2,3]. The frequency can be changed between two ASDEX...

show abstract

Design of a dual high-power, long pulse, steerable ECH launcher for DIII-D

Cited by 10 publications

References 0 publications

Performance and Upgrades for the Electron Cyclotron Heating System on DIII-D

Performance and Upgrades for the Electron Cyclotron Heating System on DIII-D

New Frequency Step-Tunable Ecrh System for Asdex Upgrade

Status of the new ECRH system for ASDEX Upgrade

Contact Info

Product

Resources

About