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10-15 May 2021
Nice, France
Europe/Vienna timezone
The Conference will be held virtually from 10-15 May 2021

First-principle based multi-channel integrated modelling in support to the design of the Divertor Tokamak Test Facility

11 May 2021, 14:00
4h 45m
Nice, France

Nice, France

Regular Poster Magnetic Fusion Theory and Modelling P2 Posters 2


Paola Mantica (Istituto per la Scienza e la Tecnologia dei Plasmi, Consiglio Nazionale delle Ricerche (CNR), 20125 Milan, Italy)


The Divertor Tokamak Test facility (DTT) [1-3] is a D-shaped superconducting tokamak (R=2.14 m, a=0.65 m, BT≤6 T, Ip≤ 5.5 MA, pulse length ≤ 100 s, auxiliary heating ≤ 45 MW, W first wall and divertor), whose construction is starting in Frascati, Italy. Its main mission is to study the controlled exhaust of energy and particle from a fusion reactor, which is a top priority research item in the European Roadmap [4] towards thermonuclear fusion power production. This will be possible in DTT by achieving large PSEP/R values (where PSEP is the power flowing through the last closed magnetic surface) using 45 MW of auxiliary heating in a high performance machine characterised by high flexibility in the choice of the divertor and of the magnetic configurations. The characteristics of the machine will allow to address many ITER and DEMO relevant physics issues besides plasma wall interaction in a fusion relevant range of plasma parameters. The heating mix foresees the use of 170 GHz ECRH, 60-90 MHz ICRH and 400 keV negative ion beam injectors, with ECRH being the main system, although the precise sharing between the three systems has still to be optimised.
In order to help with the heating system definition, and to provide scenarios for the design of diagnostics and pellet injector, or for the evaluation of issues such as ripple losses or neutron shields, it is a key priority to achieve multi-channel integrated modelling of DTT scenarios based on state-of-art first principle quasi-linear transport models, whose reliability stems from an extensive validation work against experiments and high fidelity gyrokinetic simulations carried out within the EUROfusion and ITPA frameworks (see e.g. the recent overview [5] and references therein). It is also important that the integrated modelling results for some cases are validated against gyrokinetic simulations with the specific DTT parameters, to corroborate the validity of the reduced models in the particular case of DTT. In this paper, we summarise the first results of this activity, which extends the preliminary predictions reported in 1.
The integrated modelling of DTT has been carried out with the JINTRAC suite [6] and covers the region inside the separatrix, whilst the values of temperature and density at the separatrix are taken consistently with the scrape-off layer simulations described in 1. The pedestal has been determined with the EPED1 model [7] implemented in the Europed code [8], and core-edge coupling has been taken into account on an iterative basis. The pedestal density has been set to achieve a volume averaged density <ne>~ 0.43 nGW (Greenwald limit). The region in-side the top of the pedestal has been modelled using the QuaLiKiz [9] or the TGLF [10] turbulent transport models and NCLASS [11] for the neoclassical transport. The simulations pre-dict steady-state profiles of ion and electron temperature, density, rotation, current density, impurity (Ar, W) density, and calculate a self-consistent equilibrium starting from a fixed boundary taken from [12]. The heating has been modelled self-consistently using PENCIL[13] for NBI, PION[14] for ICRH and GRAY[15] for ECRH. SANCO [16] has been used to calculate impurity ionisation and recombination and radiation. The rotation has been predicted using a semi-empirical estimate of Prandtl and pinch numbers [17] due to numerical issues using the turbulent momentum transport from the quasi-linear models.
Fig.1 shows profiles obtained for the SN full power H-mode scenario with 32 MW ECRH, 15 MW NBI and 3 MW ICRH using QuaLiKiz for turbulent transport, which is mainly driven by ion-scale ITG/TEM. The strong central ECRH peaks Te far above Ti in the central part. Ions are rather stiff and Ti stays below Te also in most of the outer region, in spite of a large amount of thermal exchange power from electrons to ions. The ne profile is moderately peaked. A peaked rotation profile with central value of 50 krad/s does not provide a significant ExB stabilisation of the ion heat transport. Global plasma parameters are βN=1.6, τE=0.28s, total DD neutron rate~1.4 1017 s-1 (30% thermal). Total radiation is 15 MW. Both Ar and W show peaked profiles, with hints of W central accumulation, however a better treatment of W neoclassical transport using NEO [18] is in plan to check this prediction. In this simulation MHD has not been included, but some considerations on MHD stability will be discussed. Similar simulations for the half-power DAY1 heating configuration yield very similar profiles and double confinement time, which is also an indication of the high stiffness. Simulations with TGLF are being finalised with the latest release of the model [19], and differences between the predictions by the two models will be assessed against gyrokinetic simulations using GENE [20].

JINTRAC simulation of DTT full power SN scenario using the QuaLiKiz transport model: a) Te, Ti, ne, nD profiles; b) Zeff, angular frequency, DD neutron profiles; c) electron and ion power dep-osition, without and with thermal exchange

1 DTT interim design report (2019)
2 Special Section of Fusion Engineering and Design Vol. 122, 2017, 253-294, e1-e25
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[19] G.M.Staebler et al., to be presented at 47th EPS Conference on Plasma Physics, Sitges, 2020
[20] F.Jenko et al., Phys. Plasmas 7 1904 (2000)

Affiliation Institute for Plasma Science and Technology, National Research Council
Country or International Organization Italy

Primary authors

Mrs Irene Casiraghi (University of Milano Bicocca) Paola Mantica (Istituto per la Scienza e la Tecnologia dei Plasmi, Consiglio Nazionale delle Ricerche (CNR), 20125 Milan, Italy) Florian Koechl (Vienna University of Technology, Institute of Atomic and Subatomic Physics)


Roberto Ambrosino (university of Naples Federico II) Jonathan Citrin (FOM DIFFER - Dutch Institute for Fundamental Energy Research) Lorenzo Frassinetti (KTH, Royal Institute of Technology) Dr Alberto Mariani (Istituto per la Scienza e Tecnologia dei Plasmi, Consiglio Nazionale delle Ricerche) Pietro Vincenzi (Consorzio RFX) Piero Agostinetti (Consorzio RFX, Italy) Benedetta Baiocchi (Istituto per la Scienza e la Tecnologia dei Plasmi) Alessandro Cardinali (ENEA Frascati Italy) Silvio Ceccuzzi (ENEA) Lorenzo Figini (Istituto per la Scienza e la Tecnologia dei Plasmi, CNR, Italy) GUSTAVO GRANUCCI (ISTITUTO PER LA SCIENZA E TECNOLOGIA DEI PLASMI- CNR) Thomas Johnson (KTH Royal Institute of Technology, Stockholm, Sweden) Piero MARTIN (Consorzio RFX) Marco Valisa (Consorzo RFX) Gregorio Vlad (Associazione Euratom-ENEA sulla Fusione)

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