Effects of a nitrogen seeded plasma on nanostructured tungsten films having fusion-relevant features

Uccello, A.; Ghezzi, F.; Laguardia, L.; Caniello, R.; Dellasega, David; Dell’Era, F.; Torre, Davide Della; Donnini, Riccardo; Granucci, G.; Mesto, Ernesto; Minelli, D.; Passoni, M.; Pedroni, Matteo; Pezzoli, Andrea; Ricci, D.

doi:10.1016/j.nme.2020.100808

Cited by 12 publications

(24 citation statements)

References 41 publications

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“…The working pressure is usually in the range 10 -1 -10 -3 Pa. Hydrogen (H), deuterium, helium (He), argon, nitrogen (N) plasmas have been considered so far. Moreover, nitrogen seeded deuterium (and hydrogen) plasmas (also with the addition of argon or helium) and helium plus ammonia mixed plasmas were used in the frame of the investigation of the ammonia production and decomposition in GyM (see Section 4; [20,21,25,30]). A 3 mm thick SST liner (2 m in length and 20.6 cm in diameter) with a plasma-sprayed tungsten coating (50 μm in thickness and an average roughness of 10 μm) on the inner surface was provisionally installed in GyM to study the role of the wall material in the ammonia formation process.…”

Section: Vacuum Vesselmentioning

confidence: 99%

“…This was done at the price of a reduced ion flux to the target holder by a factor cos θ ≃0.71. In particular, an Impac Infratherm 247/5 pyrometer can be used to directly monitor the surface temperature of the samples, which is a critical parameter to properly interpret the outcomes of PMI experiments [22,30]. Alternatively, the OES system can be connected to port 4U to study the erosion of the samples, as described in [23,24].…”

Section: Manipulators For Pmi Investigationmentioning

confidence: 99%

“…GyM was originally designed and built in 2008 to investigate basic plasma physics phenomena like turbulence and coherent structures, typical of tokamak scrape-off layer (SOL) [16][17][18]. Since 2014, the experimental program has been mainly focused on the study of PMI for fusion applications [19][20][21][22][23][24][25][26][27][28][29][30]. Most of the PWI activities have been and are presently carried out within the framework of the EUROfusion Consortium work-package plasma-facing components (WP-PFC) [3], during Horizon 2020, and its prosecutor WP plasma-wall interaction and exhaust (PWIE), in the incoming Horizon Europe.…”

Section: Introductionmentioning

confidence: 99%

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Linear plasma device GyM for plasma-material interaction studies

et al. 2023

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GyM is a linear plasma device operating at Istituto per la Scienza e Tecnologia dei Plasmi, Consiglio Nazionale delle Ricerche, Milan, with the original aim of studying basic plasma physics, such as turbulent processes. Since 2014, GyM experimental program has been mainly focused on the issue of plasma-material interaction (PMI) for magnetic confinement nuclear fusion applications. GyM consists of a stainless steel vacuum chamber (radius and length of 0.125 m and 2.11 m), a pumping system, a gas injection system, 10 magnetic field coils and two magnetron sources at 2.45 GHz, capable of delivering a total microwave power up to 4.5 kW. Highly reproducible steady-state plasmas of different gas species, at a maximum working pressure of ∼10−1 Pa, can be obtained by electron cyclotron resonance heating in the resonance layer at 87.5 mT. Plasmas of GyM have electron and ion temperature ≤15 eV and ∼0.1 eV, respectively. The electron density is in the range of 1015–1017 m−3 and the ion flux is ≤5 × 1020 ions⋅m−2s−1. Main plasma diagnostics of GyM comprise Langmuir probes, an optical emission spectrometer, a mass spectrometer and a fast camera system equipped with an image intensifier unit. For the purpose of investigating the topic of PMI, GyM is provided with two sample exposure systems. Both are biasable at a negative bias voltage down to −400 V, to tune the energy of the impinging ions. One of them is also equipped with a heating lamp and can reach and sustain a temperature of 990 K for several hours, thus allowing to study the role of sample temperature during the plasma-material interaction. This contribution presents the layout of GyM, the diagnostics, the sample exposure systems and the typical plasma parameters. A brief overview of the main PMI activities carried out so far and a description of future machine upgrades are also given.

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Section: Vacuum Vesselmentioning

confidence: 99%

Section: Manipulators For Pmi Investigationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Linear plasma device GyM for plasma-material interaction studies

et al. 2023

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“…The most probable loss channels are ion implantation into plasma-facing materials, co-deposition and NH 3 formation. These three mechanisms were investigated in laboratory experiments performed in linear device [46][47][48][49][50]. Linear devices have extensively contributed to understand the atomic and molecular processes led by N 2 injection, because of the good diagnostic accessibility and the capability of maintaining the plasma in steady-state regime for long time.…”

Section: Nitrogen Seeding Experiments In Laboratory: Formation Of Nitrides and Ammonia By Plasma Wall Interaction In Gym Linear Devicementioning

confidence: 99%

“…Fig.8N1s core-level XPS spectra of the surface and subsurface layers of a film exposed in GyM at a bias voltage of 100 V. Reproduced from Ref [49]. …”

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confidence: 99%

Theoretical and experimental aspects of non-equilibrium plasmas in different regimes: fundamentals and selected applications

et al. 2021

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This paper presents recent activities covering different plasma fields, from both theoretical and experimental point of views. An overview of the present interests of the scientific community is reported here. Starting from a brief description of the role of collisions in astrophysical plasmas, some fundamental aspects of gas discharges modelling, such as superelastic collisions and the basic concept of vibrational temperature, are discussed. Different plasma sources, as DBD and microwave discharges with their own specific applications, are reported. Edge plasmas in nuclear fusion reactors are investigated, focusing on the cooling mechanisms resulting from nitrogen puffing in the divertor region.

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