Design and RF test of a prototype traveling wave antenna for helicon current drive in KSTAR

Wi, Hyunho; Wang, S.J.; Kim, H.J.; Kwak, J.G.

doi:10.1016/j.fusengdes.2017.11.016

Cited by 24 publications

(9 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The TWA concept was presented in the early 1990s [9,19] and tested only for fast wave current drive at high frequency [13,14]. More recently, the travelling wave antenna concept has found new interests for application in the helicon current drive frequency domain [20,21] and in the lower hybrid frequency range [22]. Despite that, a test for ICRH in a metal wall machine, in steady state operation, has never been done before.…”

Section: Proposed Proof Of Principle On a Medium Sized Tokamakmentioning

confidence: 99%

A travelling wave array system as solution for the ion cyclotron resonance frequencies heating of DEMO

Ragona¹,

Messiaen²,

Ongena³

et al. 2019

Nucl. Fusion

View full text Add to dashboard Cite

Travelling Wave Array (TWA) antennas distributed along the periphery of the tokamak are presently considered as Ion Cyclotron Resonance Frequencies (ICRF) heating solution for the DEMO reactor. Compared to the conventional ICRF antenna systems currently in use or designed for future machines like ITER, the TWA consists of antenna sections integrated in the breeding blanket scattered around the machine, each one fed through a variable coupler in a resonant ring configuration. Previous modelling of an antenna system for DEMO with 16 quadruple TWA sections of 8 straps shows that a power capability exceeding 50 MW can be obtained in the frequency band of interest using the reference low coupling plasma profile of ITER. The described system optimizes the coupling to the plasma by providing a large number of radiating elements, which results in enhanced antenna directivity hereby decreasing the antenna power density. This results in a maximum strap voltage amplitude of only 15 kV and maximum inter-strap voltage amplitude of 18 kV. The generators remain matched for all loading conditions: the system is totally load resilient. Following the recommendation of the work package heating and current drive (WPHCD) Review Panel, a TWA ICRH system consisting in fewer sections concentrated in front of the equatorial ports is analysed in this paper and compared to the previous design. Reducing the number of sections increases the power density and its associated voltages. To couple 50 MW on the ITER density profile, voltages up to 30 kV are now required. Some aspects like the coupling between sections and its repercussion on the feeding network are briefly discussed. To assess the feasibility of the TWA fed by a resonant ring as ICRH system for a DEMO reactor, a test on an existing medium size tokamak is under study.

show abstract

Section: Proposed Proof Of Principle On a Medium Sized Tokamakmentioning

confidence: 99%

A travelling wave array system as solution for the ion cyclotron resonance frequencies heating of DEMO

Ragona¹,

Messiaen²,

Ongena³

et al. 2019

Nucl. Fusion

View full text Add to dashboard Cite

show abstract

“…The use of a TWA antenna for fusion applications was presented in the early 1990s [7,8] and tested for fast wave CD at 200 MHz [9]. More recently, the travelling wave antenna concept has attracted new interest for application in the helicon CD frequency range [10][11][12] and lower hybrid frequency range [13]. Previous TWA conceptual studies [6,14] developed systematic RF design calculations, geometrical optimizations and feeding solutions.…”

Section: Introductionmentioning

confidence: 99%

Pre-conceptual studies of a travelling wave array antenna for the EAST

Li¹,

Ragona²,

Hillairet³

et al. 2023

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

One of the primary problems of Ion Cyclotron Range of Frequency (ICRF) systems in magnetic confinement experiments is to couple large amount of Radio Frequency (RF) wave power through the plasma cut-off layer within the voltage limits of antenna system. Travelling Wave Array (TWA) antennas have higher coupling than conventional ICRF antennas, which is manifested in sharp and optimized k// spectrum. As a pre-study of TWA applications in the tokamaks, a TWA antenna with six consecutive straps and double-fin capacitors was conceptually designed for the Experimental Advanced Superconducting Tokamak (EAST). The antenna geometry was optimized to seek a low reflection coefficient for EAST ICRF heating scenarios. The design and simulation results of the TWA antenna are briefly presented. The results of frequency sweep in vacuum show that a bandwidth of approximately 3 MHz with S11< -30 dB can be obtained. The peak of the k// power spectrum is adjusted to～3-4 m-1 at the frequency of 34-36 MHz. In addition, the properties of power flow and characteristics of wave field are also discussed by modelling the plasma facing the TWA antenna using a cold plasma medium. The results in this study may provide some reference and guidance for the study of TWA antennas and other ICRF antennas in magnetic confined fusion devices like EAST or the Chinese Fusion Engineering Test Reactor (CFETR).

show abstract

“…TWA antennas have been successfully tested on several devices for fast wave current drive [1][2][3], lower hybrid (LH) launch [4,5] and helicon waves launch [6,7] as well as plasma production [1] and plasma start-up [5]. This type of antenna presents several advantages: (i) TWAs' power spectrum have a narrow toroidal extent, leading to directional fast waves and enabling localized power deposition into the core plasma [1,8].…”

Section: Introductionmentioning

confidence: 99%

Minimization of the edge modes and near fields of a travelling wave array antenna for WEST

Maquet,

Ragona,

Durodié

et al. 2023

Nucl. Fusion

View full text Add to dashboard Cite

The Travelling Wave Array (TWA) antenna has been proposed as a promising alternative for Ion Cyclotron Resonant Heating (ICRF) in future fusion reactors. In this study, the possibility to make a TWA compatible with a tungsten environment like the WEST tokamak is assessed. For this purpose, two aspects of the antenna are investigated: the power spectrum and the near fields excited by the antenna. The sensitivity of these parameters to load and capacitor layout variations is taken into account while satisfying a proper antenna frequency response. The sensitivity of the power spectrum to frequency variation is also investigated to allow the possibility of fast feedback of the power deposition into the core plasma of WEST. The high resilience of the TWA to these variations is demonstrated and the main parameters of the TWA expected in WEST are compared to a current WEST antenna for the same loading. Possible optimizations of the TWA antenna are discussed. The present study is fully transferable to a fusion reactor like DEMO or ARC.

show abstract

Design and RF test of a prototype traveling wave antenna for helicon current drive in KSTAR

Cited by 24 publications

References 17 publications

A travelling wave array system as solution for the ion cyclotron resonance frequencies heating of DEMO

A travelling wave array system as solution for the ion cyclotron resonance frequencies heating of DEMO

Pre-conceptual studies of a travelling wave array antenna for the EAST

Minimization of the edge modes and near fields of a travelling wave array antenna for WEST

Contact Info

Product

Resources

About