F. Kazarian

A lower hybrid current drive system for ITER

A 20 MW/5 GHz lower hybrid current drive (LHCD) system was initially due to be commissioned and used for the second mission of ITER, i.e. the Q = 5 steady state target. Though not part of the currently planned procurement phase, it is now under consideration for an earlier delivery. In this paper, both physics and technology conceptual designs are reviewed. Furthermore, an appropriate work plan is also developed. This work plan for design, R&D, procurement and installation of a 20 MW LHCD system on ITER follows the ITER Scientific and Technical Advisory Committee (STAC) T13-05 task instructions. It gives more details on the various scientific and technical implications of the system, without presuming on any work or procurement sharing amongst the possible ITER partners(b). This document does not commit the Institutions or Domestic Agencies of the various authors in that respect.

LOWER HYBRID CURRENT DRIVE IN TORE SUPRA

Abstract Since the mission of Tore Supra is to produce quasi-steady-state discharges, the lower hybrid current drive (LHCD) system constitutes the most important method of additional heating and noninductive current drive. A description of the LHCD system is given, including the different launcher designs developed for the Tore Supra long-pulse program. Following the completion of the Composants Internes et Limiteur project, together with the installation of a high-performance LHCD launcher, world record discharges, injected and extracted energy exceeding 1 GJ, were obtained in 2003. With the flexibility of lower hybrid (LH) waves to tailor the current profile, an enhanced performance regime, the so-called LHEP, has been maintained in quasi-steady-state discharges. Detailed measurements of the fast electron distribution have allowed us to constrain LHCD ray-tracing models and to quantify parametric dependencies describing the fast electron tail. Localized heat loads on the LHCD launchers due to interaction with fast particles have been measured and quantified, using infrared imaging and calorimetric measurements on water-cooled plasma facing components. Furthermore, experimental results in the area of LH wave coupling are presented.

Status of the ITER IC H&CD System

The ITER Ion Cyclotron Heating and Current Drive system will deliver 20 MW of radio frequency power to the plasma in quasi continuous operation during the different phases of the experimental programme. The system also has to perform conditioning of the tokamak first wall at low power between main plasma discharges. This broad range of requirements imposes a high flexibility and a high availability. The paper highlights the physics and design requirements on the IC system, the main features of its subsystems, the predicted performance, and the current procurement and installation schedule.

Concept development for the ITER equatorial port visible/infrared wide angle viewing systema)

The ITER equatorial port visible∕infrared wide angle viewing system concept is developed from the measurement requirements. The proposed solution situates 4 viewing systems in the equatorial ports 3, 9, 12, and 17 with 4 views each (looking at the upper target, the inner divertor, and tangentially left and right). This gives sufficient coverage. The spatial resolution of the divertor system is 2 times higher than the other views. For compensation of vacuum-vessel movements, an optical hinge concept is proposed. Compactness and low neutron streaming is achieved by orienting port plug doglegs horizontally. Calibration methods, risks, and R&D topics are outlined.

Overview on Experiments On ITER‐like Antenna On JET And ICRF Antenna Design For ITER

Following an overview of the ITER Ion Cyclotron Resonance Frequency (ICRF) system, the JET ITER‐like antenna (ILA) will be described. The ILA was designed to test the following ITER issues: (a) reliable operation at power densities of order 8 MW/m2 at voltages up to 45 kV using a close‐packed array of straps; (b) powering through ELMs using an internal (in‐vacuum) conjugate‐T junction; (c) protection from arcing in a conjugate‐T configuration, using both existing and novel systems; and (d) resilience to disruption forces. ITER‐relevant results have been achieved: operation at high coupled power density; control of the antenna matching elements in the presence of high inter‐strap coupling, use of four conjugate‐T systems (as would be used in ITER, should a conjugate‐T approach be used); operation with RF voltages on the antenna structures up to 42 kV; achievement of ELM tolerance with a conjugate‐T configuration by operating at 3Ω real impedance at the conjugate‐T point; and validation of arc detection sys...

Ion Cyclotron Power Source System For ITER

Abstract The ITER ion cyclotron heating and current drive system is designed to deliver 20 MW to a broad range of plasma scenarios, during very long pulses (∼500 s in inductive, up to 1 h in noninductive, plasma scenarios). The associated radio-frequency (rf) source system has to be compliant with all operation modes foreseen in ITER operation. India is responsible for delivering the rf source package to ITER, which includes one prototype rf source followed by eight bulk production units. This lecture presents the ITER rf source system, design considerations, and status of the research and development program to identify and resolve the major technological challenges involved.

ITER ICRF system: R&D progress and technical choices

This paper describes the ITER ICRF system main requirements and the latest developments for its different parts which are to be procured by the ITER Parties. The built in margins will allow reaching the requirements on a large parameter range, or delivering more power in a restricted range.

Status of the ITER ion cyclotron heating and current drive system

The paper reports on latest developments for the ITER Ion Cyclotron Heating and Current Drive system: imminent acceptance tests of a prototype power supply at full power; successful factory acceptance of candidate RF amplifier tubes which will be tested on dedicated facilities; further design integration and experimental validation of transmission line components under 6MW hour-long pulses. The antenna Faraday shield thermal design has been validated above requirements by cyclic high heat flux tests. R&D on ceramic brazing is under way for the RF vacuum windows. The antenna port plug RF design is stable but major evolution of the mechanical design is in preparation to achieve compliance with the load specification, warrant manufacturability and incorporate late interface change requests. The antenna power coupling capability predictions have been strengthened by showing that, if the plasma scrape-off layer turns out to be steep and the edge density low, the reference burning plasma can realistically be di...

ITER project and RF systems

ITER is an international project supported by seven partners: China, Europe, India, Japan, Korea, Russian Federation and USA. Formally established in 2006, construction has started in France, more precisely in Provence. General progress of the project is presented followed by a focus on the RF systems which will provide 40 MW into the plasma, based on systems around 50 MHz and 170 GHz. These systems are using high power grid tubes, gyrotrons, and the latest power supplies technology to feed kilometres of transmission lines connected to specific antennas located at a few centimeters from the hot burning plasma.

A Lower Hybrid Current Drive System for ITER and High Power CW Klystron Development

A 20 MW/5 GHz Lower Hybrid Current Drive (LHCD) system was initially due to be commissioned and used for the second mission of ITER, i.e. the Q = 5 steady state target. Though not part of currently planned procurement phase, it is now under consideration for an earlier delivery. An LH program has been initiated under EFDA, following the ITER STAC recommendation, to provide a pre‐design document including the conceptual design, costing, possible procurement allocation, WBS and R&D needs.