The ASDEX upgrade ICRH antenna

Noterdaeme, Jean-Marie; Wesner, F.; Brambilla, M.; Fritsch, R.; Kutsch, Horst; Söll, M.; Team, Icrh

doi:10.1016/0920-3796(94)90037-x

Cited by 25 publications

(14 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…ASDEX Upgrade (AUG) has four ICRF antennas located at the low field side, each antenna consisting of two straps [8]. The antenna straps are connected to resonant lines with 25 X characteristic impedance (Ôstrap resonant linesÕ) which are then connected via a T to the matching circuit (two stub tuners).…”

Section: Icrf Antennas At Asdex Upgrade and Rf Measurementsmentioning

confidence: 99%

Influence of ELMs on operation of ICRF antennas in ASDEX Upgrade

Bobkov

Braun

Hartmann

et al. 2005

Journal of Nuclear Materials

Self Cite

View full text Add to dashboard Cite

Section: Icrf Antennas At Asdex Upgrade and Rf Measurementsmentioning

confidence: 99%

Influence of ELMs on operation of ICRF antennas in ASDEX Upgrade

Bobkov

Braun

Hartmann

et al. 2005

Journal of Nuclear Materials

Self Cite

View full text Add to dashboard Cite

“…The details of the setup can be found in [13]; the network section including the common line, matching network, individual feeding lines and straps, and the relevant RF diagnostics is shown schematically in figure 1. Note that the straps are not fed at the same poloidal location, and the current facing the plasma flows in opposite directions when the ports are fed with the same phasing (see [9] for details).…”

Section: The Asdex Upgrade Icrf System and Diagnosticsmentioning

confidence: 99%

“…Not shown are the voltage probe arrays on each 25 Ω feeding line, which are not used in this study. Note that this schematic is only meant to show the available diagnostics and main features of each system, and does not show the real strap geometry (which is examined in detail in [9]). …”

Section: The Asdex Upgrade Icrf System and Diagnosticsmentioning

confidence: 99%

“…The ICRF system at ASDEX Upgrade consists of four two-strap antennas (antennas 1 -3 being baseline [9] and antenna 4 being a wide limiter, narrow strap antenna designed to reduce RF sheaths and hence W sputtering [10]). The four antennas were connected into two double systems, where the output power of two RF generators was combined and then split into two 50 Ω lines by means of 3 dB couplers for ELM protection (details can be found in [11] and [12]); each line was connected to a matching section (consisting of two parallel tuning stubs) and split into two 25 Ω lines feeding the two antenna straps.…”

Section: The Asdex Upgrade Icrf System and Diagnosticsmentioning

confidence: 99%

See 1 more Smart Citation

A detailed comparison of antenna impedance measurements on ASDEX Upgrade with the ion cyclotron range of frequencies antenna code TOPICA

et al. 2015

Self Cite

View full text Add to dashboard Cite

Abstract. New antenna diagnostics on ASDEX Upgrade, in the form of voltage and current probe pairs on the feeding lines of each ICRF antenna, close to the input ports, has made it possible to study in detail the behavior of the ASDEX Upgrade two-strap antenna under changing loading conditions, and compare these measurements with results of simulations using the TOPICA code. The present work extends previous studies by using the input impedance (more precisely, the complex voltage reflection coefficient Γ) on each antenna port for comparison, instead of the more commonly used loading resistance or coupled power. The electron density profiles used for the simulation were reconstructed from DCN interferometer and Lithium beam emission spectroscopy measurements, ELMsynchronized and averaged over time intervals from 10 to 200 ms depending on the case; 112 cases were compared from seven ASDEX Upgrade discharges with widely different plasma parameters and two operating frequencies (30 and 36.5 MHz). Very good agreement in |Γ| is found with the measurements on antenna 3 (< 3% averaged over a shot), good agreement is found with antennas 1 and 2 (< 10%); the code reproduces the correct trend in loading resistance R L in a significant majority of cases, although the discrepancies in the absolute values can be rather high (up to ∼ 50%) due to high reflection. Sources of discrepancy are discussed.PACS numbers: 52.50.Qt TOPICA study on ASDEX Upgrade 2

show abstract

“…The matching system uses a double stub tuner system at each of the four antennas, each antenna is a double loop antenna [4]. In the recent years the antenna has been only modified in details like the cross section of the antenna loop to reduce edge electric fields, the addition of holes in the central conduction to allow better pumping, etc.…”

Section: Matching and Transmission Line Lossesmentioning

confidence: 99%

An improved method to measure the antenna resistance and radiated power of ICRF-antennas using current probes

Faugel¹,

Bobkov²,

Braun³

et al. 2011

Fusion Engineering and Design

Self Cite

View full text Add to dashboard Cite

The coupling properties of ICRF antennas depend on the plasma boundary characteristics, which are modified for example by H-Mode or ELMs. The impedance and the power into the antenna feeding line are measured with a pair of directional couplers near the double stub tuner matching system. Those measurements include the losses of the transmission line and the antenna. An approach to separate the radiated power from the losses is to measure the current in the antenna loops. To measure the current in the short of the antenna loop two current probes have been installed near the short of the antenna loops in one of the ICRF antennas during the 2009/2010 shutdown of ASDEX Upgrade. These signals allow a new approach in calculating the antenna resistance and the launched power and can be used to separate the launched power from the losses in the matching system and transmission lines up to the antenna. Although the calibration of the signal amplitude from the current probes needs further investigation, the amplitude is proportional to the current in the antenna loop. With those probes and a new real-time DSP-based system, the radiated (as opposed to the total power i.e. including loss power) power can be feedback controlled.

show abstract

The ASDEX upgrade ICRH antenna

Cited by 25 publications

References 6 publications

Influence of ELMs on operation of ICRF antennas in ASDEX Upgrade

Influence of ELMs on operation of ICRF antennas in ASDEX Upgrade

A detailed comparison of antenna impedance measurements on ASDEX Upgrade with the ion cyclotron range of frequencies antenna code TOPICA

An improved method to measure the antenna resistance and radiated power of ICRF-antennas using current probes

Contact Info

Product

Resources

About