Simultaneous H/D/T and 3He/4He absolute concentration measurements with an optical Penning gauge on JET

Vartanian, S.; Delabie, E.; Jepu, I.; Jacquet, Philippe; Lerche, E.; Lomanowski, B.; Colas, L.; Marcus, Chris; Dumond, R.; Douai, D.; Widdowson, A.; Contributors, Jet

doi:10.1016/j.fusengdes.2021.112511

Cited by 29 publications

(28 citation statements)

References 6 publications

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“…The concentration of the different hydrogenic species, H, D and T, were continuously monitored with an optical Penning (or species-selective Penning) gauge in the JET subdivertor region as described in references [25,26]. It measures the concentration of one hydrogenic species relative to the total concentration of all hydrogenic species.…”

Section: Experimental Strategy and Dynamics Of L-h Transition Pulsesmentioning

confidence: 99%

The power threshold of H-mode access in mixed hydrogen–tritium and pure tritium plasmas at JET with ITER-like wall

Birkenmeier

Solano²,

Lerche

et al. 2022

Nucl. Fusion

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The heating power to access the high confinement mode (H-mode), PLH, scales approximately inversely with the isotope mass of the main ion plasma species as found in (protonic) hydrogen, deuterium and tritium plasmas in many fusion facilities over the last decades. In first dedicated L-H transition experiments at the Joint European Torus (JET) tokamak facility with the ITER-like wall (ILW), the power threshold, PLH , was studied systematically in plasmas of pure tritium and hydrogen- tritium mixtures at a magnetic field of 1.8 T and a plasma current of 1.7 MA in order to assess whether this scaling still holds in a metallic wall device. The measured power thresholds, PLH, in Ohmically heated tritium plasmas agree well with the expected isotope scaling for metallic walls and the lowest power threshold was found in Ohmic phases at low density. The measured power thresholds in ion cyclotron heated plasmas of pure tritium or hydrogen-tritium mixtures are significantly higher than the expected isotope mass scaling due to higher radiation levels. However, when the radiated power is taken into account, the ion cyclotron heated plasmas exhibit similar power thresholds as a neutral beam heated plasma, and are close to the scaling. The tritium plasmas in this study tended to higher electron heating fractions and, when heated with ion cyclotron waves, to relatively higher radiation fractions compared to other isotopes potentially impeding access to sustained H-modes.

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Section: Experimental Strategy and Dynamics Of L-h Transition Pulsesmentioning

confidence: 99%

The power threshold of H-mode access in mixed hydrogen–tritium and pure tritium plasmas at JET with ITER-like wall

Birkenmeier

Solano²,

Lerche

et al. 2022

Nucl. Fusion

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“…Not included in this paper is a discussion of the effect of plasma-surface interactions inside the Penning discharge tube, where neutrals are ionized and plasma light emission is produced in the process, and then used to determine the concentrations of the emitting species. This interaction, in particular in the form of hydrogen desorption from Penning electrode stainless steel surfaces (as well as isotopic exchange effects) is suspected to play a role in the detected systematic shift of the OGA-based H-content data and is a topic of current laboratory studies [16]. Even including this effect, it is clear that, for DTE2, presently upgraded, sub-divertor gas analysis capability is expected to provide measurement minimally down to the 1% level in support of JET DTE2 campaign needs.…”

Section: Discussionmentioning

confidence: 99%

“…discussion on surface interaction in the plasma source in [5]). Direct, laboratory studies of these interactions, using the same plasma sources and deploying baking under controlled conditions, as well as a model to describe these processes, are presently under way [16].…”

Section: The Average Value ¨δ[H]mentioning

confidence: 99%

Sub-divertor fuel isotopic content detection limit for JET and its impact on ICRF core heating and DTE2 operation

et al. 2019

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The ability to detect and control fuel isotopic content down to a 1% concentration level is greatly important for the upcoming JET DTE2 campaign, as well as its associated TT and DD phases. A reduction of H minority concentration even from 2% down to 1% is shown here to have significant impact on the effectiveness of ion cyclotron range of frequencies core heating, while the ability to maintain T or D concentration at or below 1% is critical to limiting fusion neutron generation in the DD and TT phases, correspondingly. The sub-divertor measurement of (global) isotopic concentration, based on Penning-activated optical spectroscopy, can deliver minimally this 1% detection for DTE2 as long as light collection from the Penning emission can be optimized and gradual window transmission deterioration can be minimized. This is simulated International Atomic Energy Agency

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“…An example is the threeion 4 He-( 3 He)-H ICRF scheme, recently applied for heating non-active H-4 He plasmas at JET. In these experiments, for the first time, an enhanced high-resolution sub-divertor residual gas analyser [31], as planned for ITER, provided simultaneous measurements of 4 He and 3 He concentrations (n( 4 He)/n e ≈ 10%, n( 3 He)/n e ≈ 0.2%). The experiments were accompanied by good progress in modelling three-ion ICRF scenarios.…”

Section: Radio Frequency Heating Schemes For Iter Pfpo and D-t Operationmentioning

confidence: 99%

Overview of JET results for optimising ITER operation

et al. 2022

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The JET 2019-2020 scientific and technological programme exploited the results of years of concerted scientific and engineering work, including the ITER-like wall (ILW: Be wall and W divertor) installed in 2010, improved diagnostic capabilities now fully available, a major Neutral Beam Injection (NBI) upgrade providing record power in 2019-2020, and tested the technical & procedural preparation for safe operation with tritium. Research along three complementary axes yielded a wealth of new results. Firstly, the JET plasma programme delivered scenarios suitable for high fusion power and alpha particle physics in the coming D-T campaign (DTE2), with record sustained neutron rates, as well as plasmas for clarifying the impact of isotope mass on plasma core, edge and plasma-wall interactions, and for ITER pre-fusion power operation. The efficacy of the newly installed Shattered Pellet Injector for mitigating disruption forces and runaway electrons was demonstrated. Secondly, research on the consequences of long-term exposure to JET-ILW plasma was completed, with emphasis on wall damage and fuel retention, and with analyses of wall materials and dust particles that will help validate assumptions and codes for design & operation of ITER and DEMO. Thirdly, the nuclear technology programme aiming to deliver maximum technological return from operations in D, T and D-T benefited from the highest D-D neutron yield in years, securing results for validating radiation transport and activation codes, and nuclear data for ITER.

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Simultaneous H/D/T and 3He/4He absolute concentration measurements with an optical Penning gauge on JET

Cited by 29 publications

References 6 publications

The power threshold of H-mode access in mixed hydrogen–tritium and pure tritium plasmas at JET with ITER-like wall

The power threshold of H-mode access in mixed hydrogen–tritium and pure tritium plasmas at JET with ITER-like wall

Sub-divertor fuel isotopic content detection limit for JET and its impact on ICRF core heating and DTE2 operation

Overview of JET results for optimising ITER operation

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