Design concepts of machine upgrades for the RFX-mod experiment

Peruzzo, S.; Agostini, M.; Agostinetti, P.; Bernardi, M.; Bettini, Paolo; Bolzonella, T.; Canton, A.; Carraro, L.; Cavazzana, R.; Bello, S. Dal; Palma, M. Dalla; Delogu, R.; Fassina, A.; Grando, L.; Innocente, P.; Marchiori, G.; Marconato, N.; Marrelli, L.; Patel, Nisarg; Puiatti, M. E.; Scarin, P.; Siragusa, M.; Sonato, P.; Spolaore, M.; Trevisan, L.; Valisa, M.; Vallar, M.; Vincenzi, P.; Zamengo, A.; Zanca, P.; Zanotto, L.

doi:10.1016/j.fusengdes.2017.03.056

Cited by 23 publications

(12 citation statements)

References 5 publications

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“…Based on the results here presented and in order to extend the explored parameter range, some enhancements for the RFX-mod device (RFX-mod2 after upgrading) have been proposed and are presently in the final design phase [75,76]. These can be summarized as: 1) upgrade of the magnetic front-end to reduce the residual magnetic chaos;…”

Section: Proposed Device Upgradesmentioning

confidence: 99%

Overview of the RFX-mod fusion science activity

Zuin¹,

Bello²,

Marrelli³

et al. 2017

Nucl. Fusion

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This paper reports the main recent results of the RFX-mod fusion science activity. The RFX-mod device is characterized by a unique flexibility in terms of accessible magnetic configurations. Axisymmetric and helically shaped Reversed-field pinch equilibria have been studied, along with tokamak plasmas in a wide range of q(a) regimes (spanning from 4 down to 1.2 values). The full range of magnetic configurations in between the two, the so-called ultra low-q ones, has been explored, with the aim of studying specific physical issues common to all equilibria, such as, for example, the density limit phenomenon. The powerful RFX-mod feedback control system has been exploited for MHD control, which allowed to extend the range of experimental parameters, as well as to induce specific magnetic perturbations for the study of 3D effects. In particular, transport, edge and isotope effect in 3D equilibria have been investigated, along with runaway mitigations through induced magnetic perturbations. The first transitions to an improved confinement scenario in circular and D-shaped tokamak plasmas have been obtained thanks to an active modification of the edge electric field through a polarized electrode. The experiments are supported by intense modelling with 3D MHD, gyrokinetic, guiding center and transport codes. Proposed modifications to the RFX-mod device, which will enable further contributions to the solution of key issues in the roadmap to ITER and DEMO, are also briefly presented.

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Section: Proposed Device Upgradesmentioning

confidence: 99%

Overview of the RFX-mod fusion science activity

Zuin¹,

Bello²,

Marrelli³

et al. 2017

Nucl. Fusion

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“…In this contribution, we present the main features of the Plasma Position Reflectometry (PPR) system to be installed on the RFX-mod2 device [3,4], the upgraded version of RFX-mod [5]. The PPR system is considered a good candidate as a backup system of magnetic sensors for control purposes, due to its ability to withstand reactor conditions and being the electron density radial profile a direct estimate of edge plasma-wall distance [6].…”

Section: Introductionmentioning

confidence: 99%

Design of a new reflectometric system for real time plasma position control on the RFX-mod2 device

Cavazzana¹,

Abate²,

Bernardi³

et al. 2022

J. Inst.

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RFX-mod2 (R = 2.0 m, a = 0.49 m), the upgraded version of the previous RFXmod fusion device, will be equipped with a new reflectometry system specifically designed for plasma position control purposes. Featuring a high temporal and spatial resolution and being suitable for harsh fusion reactor experimental conditions (long pulses, high neutron fluxes), reflectometry has been proposed as a good candidate for this task. On RFX-mod2 the diagnostic system will consist of four bistatic ultrafast independent reflectometric units working in the frequency range (16–26.5 GHz) and installed in four different poloidal locations at the same toroidal angle: two on the equatorial plane (high field side/low field side) and two at the vertical top/bottom ports. Standard pyramidal horns will be installed in the external midplane and in the vertical ports, while parabolic hoghorn reflectors have been designed for the internal midplane. Different technical solutions for the integration in the machine, as the additive manufacturing for the antenna production, are presented. Despite the differences with respect to the application on large Tokamaks like DEMO, the RFX-mod2 plasma position reflectometer can contribute to test on a simple machine some of the issues related to the development of a reflectometry based plasma position and shape control.

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“…Both these experiments were equipped with a microwave multiband reflectometric system to measure the boundary plasma density [3,4], consisting of 4 conical antennas installed in a low field size (LFS) equatorial access to the plasma. The new RFX-mod2 [5] single band (16-26.5 GHz) reflectometric system will instead consist of 4 pairs of transmitting/receiving antennas placed within dedicated plasma accesses in 4 poloidal positions. It has been designed to work in X-mode wave propagation in tokamak discharges [6].…”

Section: Introductionmentioning

confidence: 99%

Design of the high field side antenna of the new reflectometric system for plasma position estimate in RFXmod2

Marchiori¹,

Cavazzana²,

Moresco³

2022

J. Inst.

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A reflectometric system will be installed in the RFX-mod2 experiment, consisting of 4 couples of transmitting/receiving antennas working in the range 16–26.5 GHz in X-mode wave propagation for tokamak discharges. They will be placed within dedicated plasma accesses in the same poloidal section at 4 equispaced poloidal positions, two on the equatorial plane, High Field Side (HFS)/Low Field Side (LFS), and two at the vertical top/bottom ports. This configuration was conceived to perform plasma position control experiments without using the magnetic measurement signals. While the accesses in LFS, top and bottom positions will accommodate pyramidal antennas, the strict room constraints in the HFS position required a special routing of the feeding waveguide and the design of a different type of antenna, described in the paper. The horn reflector (also named hoghorn) type was preferred which allows radiating (and receiving) a beam at a 90° direction with respect to the horn axis, which will be perpendicular to the equatorial plane. After fixing a reference working frequency f = 21 GHz (wavelength λ = 14.3 mm), an antenna fitting the available room was designed by means of the COMSOL Multiphysics Radio Frequency module. Four different versions were developed by introducing some modifications of the aperture shape to study their effect on the antenna performance. FEM analyses were run for frequencies in the 17–26 GHz interval to characterize the frequency response in terms of radiative patterns of the total and far electric field. The directivity of the antennae was also evaluated. The 4 versions exhibited comparable responses and the observed beam directional properties at the expected plasma distance were considered acceptable for the development of this application. A prototype of the antenna has been realized by additive manufacturing process.

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Design concepts of machine upgrades for the RFX-mod experiment

Cited by 23 publications

References 5 publications

Overview of the RFX-mod fusion science activity

Overview of the RFX-mod fusion science activity

Design of a new reflectometric system for real time plasma position control on the RFX-mod2 device

Design of the high field side antenna of the new reflectometric system for plasma position estimate in RFXmod2

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