New infrared imaging diagnostic for the Neutral Beam Heating System at the TJ-II stellarator

Liniers, M.; Quintana, José A.; Rojo, B.; Martín-Díaz, F.; Miguel, Francisco Javier Tamayo de; Sebastián, J.A.; Carrasco, R. C.; Soleto, A.; Sánchez-Sarabia, E.; Jiménez-Denche, A.; Pastor, C.; Rodriguez, C.; Guasp, J.; Cal, E. de la; McCarthy, K. J.; Pastor, I.; Ascasíbar, E.

doi:10.1088/1748-0221/14/09/c09028

Cited by 6 publications

(4 citation statements)

References 9 publications

(14 reference statements)

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“…From the results of the simulations with BBNBI, we can estimate the power loads to the wall due to shine through (ST) and compare with the measurements taken by an infrared camera (IRC) recently commissioned in TJ-II for this purpose [34]. In principle, the experimental temperature rise in the vacuum vessel at the beam impact location (beam stop) due to a continuous injection is given by…”

Section: Shine Throughmentioning

confidence: 99%

Validating neutral-beam current drive simulations in the TJ-II stellarator

Mulas¹,

Cappa²,

Martínez-Fernández³

et al. 2023

Preprint

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In this paper, we analyze the results of neutral-beam current drive (NBCD) experiments, performed in the TJ-II stellarator, with the aim of validating the theoretical predictions. Both parallel and anti-parallel injection with respect to the magnetic field were explored using co (NBI1) and counter (NBI2) beams at different injected beam power and plasma densities. The fast-ion current driven by both beams was simulated with the Monte Carlo code ASCOT and the electron response to the fast-ion current was calculated analytically using a model valid for an arbitrary magnetic configuration and a low collisionality plasma. The model reproduces with rather good agreement the toroidal current measured in NBI2 plasmas while the current driven by NBI1 is less than half the predicted one. Possible reasons for this discrepancy are discussed.

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Section: Shine Throughmentioning

confidence: 99%

Validating neutral-beam current drive simulations in the TJ-II stellarator

Mulas¹,

Cappa²,

Martínez-Fernández³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…From the results of the simulations with BBNBI, we can estimate the power loads to the wall due to ST and compare with the measurements taken by an infrared camera (IRC) recently commissioned in TJ-II for this purpose [35]. In principle, the experimental temperature rise in the vacuum vessel at the beam impact location (beam stop) due to a continuous injection is given by…”

Section: Shine Throughmentioning

confidence: 99%

Validating neutral-beam current drive simulations in the TJ-II stellarator

Mulas¹,

Cappa²,

Martínez³

et al. 2023

Nucl. Fusion

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In this paper, we analyze the results of neutral-beam current drive (NBCD) experiments performed in the TJ-II stellarator with the aim of validating the theoretical predictions. Both parallel and anti-parallel injection with respect to the magnetic field were explored using co (NBI1) and counter (NBI2) beams at different injected beam power and plasma densities. The fast-ion current driven by both beams was simulated with the Monte Carlo code ASCOT and the electron response to the fast-ion current was calculated analytically using a model valid for an arbitrary magnetic configuration and a low collisionality plasma. Despite the uncertainties associated to the determination of experimental inputs, the model reproduces with rather good agreement the toroidal current measured in NBI2 plasmas. However, the current driven by NBI1 is less than half the predicted one. Possible reasons for this discrepancy are discussed. Among the probable causes, the most likely is the increased presence of lithium in the plasma when NBI1 is injected, this being the result of its irregular deposition during wall conditioning.

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“…In parallel, the majority ion central temperature, T i0 , is 80 eV. Additional heating is available from two tangential neutral beam injection (NBI) systems operated in a counter/co-counter configuration [5]. With these, up to ∼1 MW can be injected into the vacuum chamber for up to 120 ms and n e0 , T e0 , and T i0 up to 5 × 10 19 m −3 , 400 eV, and 120 eV, respectively, can be achieved with a boron plus lithium coating on the inner wall [6].…”

Section: Jinst 16 C12026mentioning

confidence: 99%

“…Finally, several camera systems are also used on TJ-II. For instance, infrared cameras (IRCs) are operated to estimate total beam power absorbed by the plasma when NBI heating is used [5]. For this, the temperature rise of in-vacuum graphite beam dumps, due to shine-through, is determined using thermographic analysis.…”

Section: Camera Diagnosticsmentioning

confidence: 99%

Plasma diagnostic systems and methods used on the stellarator TJ-II

McCarthy¹

2021

J. Inst.

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The TJ-II is a heliac-type stellarator device with major radius of 1.5 m and averaged minor radius ⩽0.22 m that has been operated at CIEMAT, Madrid since 1998. Its full magnetic field is created by a system of poloidal, central, toroidal and vertical field coils, thus it possesses a fully 3-dimensional plasma structure and a bean-shaped plasma cross-section. Although this results in a complicated vacuum-vessel layout, it has excellent port access for diagnostics (96 portholes). During its initial operational phase, it was equipped with a limited set of essential diagnostics. Since then, a broad variety and large number of both passive and active diagnostics have been installed. The former include Hα monitors, light spectrometers, an electron cyclotron emission radiometer, X-ray filter monitors, neutral particle analysers, magnetic diagnostics, as well as cameras, among others, while the latter include various laser, atomic and ion beam based diagnostics, microwave probe beams, Langmuir probes plus impurity injection techniques. In this paper, after describing the TJ-II stellarator, its heating and fuelling systems, the diagnostic systems employed are outlined and discussed briefly here. Finally, results obtained with selected systems are highlighted.

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New infrared imaging diagnostic for the Neutral Beam Heating System at the TJ-II stellarator

Cited by 6 publications

References 9 publications

Validating neutral-beam current drive simulations in the TJ-II stellarator

Validating neutral-beam current drive simulations in the TJ-II stellarator

Validating neutral-beam current drive simulations in the TJ-II stellarator

Plasma diagnostic systems and methods used on the stellarator TJ-II

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