Analysis of initial stage of plasma discharge in tokamaks: mathematical model formulation, simulation results, comparison with experiments

Belyakov, V. A.; Vasiliev, V. I.; Lobanov, K.M.; Makarova, L.P.; Mineev, A. B.

doi:10.1109/phycon.2003.1237045

Cited by 9 publications

(12 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2012), SCENPLINT (Belyakov et al. 2003 a , b ) and BKD0 (Granucci et al. 2015) codes, which were carefully benchmarked against each other recently in Kim et al.…”

Section: Verification Of the Burn-through Modelmentioning

confidence: 99%

See 1 more Smart Citation

Runaway electron generation during tokamak start-up

Hoppe

et al. 2022

J. Plasma Phys.

View full text Add to dashboard Cite

Tokamak start-up is characterized by low electron densities and strong electric fields, in order to quickly raise the plasma current and temperature, allowing the plasma to fully ionize and magnetic flux surfaces to form. Such conditions are ideal for the formation of superthermal electrons, which may reduce the efficiency of ohmic heating and prevent the formation of a healthy thermal fusion plasma. This is of particular concern in ITER where engineering limitations put restrictions on the allowable electric fields and limit the prefill densities during start-up. In this study, we present a new 0D burn-through simulation tool called STREAM (STart-up Runaway Electron Analysis Model), which self-consistently evolves the plasma density, temperature and electric field, while accounting for the generation and loss of relativistic runaway electrons. After verifying the burn-through model, we investigate conditions under which runaway electrons can form during tokamak start-up as well as their effects on the plasma initiation. We find that Dreicer generation plays a crucial role in determining whether a discharge becomes runaway-dominated or not, and that a large number of runaway electrons could limit the ohmic heating of the plasma, thus preventing successful burn-through or further ramp-up of the plasma current. The runaway generation can be suppressed by raising the density via gas fuelling, but only if done sufficiently early. Otherwise a large runaway seed may have already been built up, which can avalanche even at relatively low electric fields and high densities.

show abstract

“…2012), SCENPLINT (Belyakov et al. 2003 a , b ) and BKD0 (Granucci et al. 2015) codes, which were carefully benchmarked against each other recently in Kim et al.…”

Section: Verification Of the Burn-through Modelmentioning

confidence: 99%

“…The code currently used for ITER start-up development – the SCENPLINT code (Belyakov et al. 2003 a , b ) – does include effects of runaway electrons, but it uses simplified models for the runaway generation rates.…”

Section: Introductionmentioning

confidence: 99%

Runaway electron generation during tokamak start-up

Hoppe

et al. 2022

J. Plasma Phys.

View full text Add to dashboard Cite

show abstract

“…The evolution of an impurity content in a plasma was treated in the SCENPLINT code with an exponentially growing function, i.e. n c /n e ≡ 0.013 + 0.03((1 − exp(−t (s)/0.25))) [3,7,8].…”

Section: Introductionmentioning

confidence: 99%

Enhancement of plasma burn-through simulation and validation in JET

et al. 2012

View full text Add to dashboard Cite

In this paper, a new burn-through model is introduced in detail, and the quantative validation of the simulation results against JET data is presented for the first time. In order to calculate the particle confinement time, a dynamic effective connection length model including an eddy current effect is used assuming ambipolar transonic transport and Bohm diffusion model for parallel and perpendicular particle losses, respectively. Plasma-Surface Interaction (PSI) effect is treated with an impurity sputtering yield and an exponential decay model of the deuterium recycling coefficient. The rate and power coefficients in the Atomic Data and Analysis Structure (ADAS) package are adopted to solve energy and particle balance. The neutral screening effects are taken into account according to particle species, and the sophisticated energy and particle balances are presented. The new burn-through simulation shows good agreement against carbon wall JET data. This indicates that the burn-through simulation can be applied to investigate the key aspect of physics in plasma burn-through and to perform a predictive simulation for ITER start-up.

show abstract

“…The investigation of plasma burn-through has been published only with 0D simulations [7,11,29,30]. Since the closed flux surfaces (CFSs) are not established yet during the plasma burn-through phase at low plasma current, a 2D approach of numerical simulation is extremely difficult.…”

Section: Discussionmentioning

confidence: 99%

Physics of plasma burn-through and DYON simulations for the JET ITER-like wall

Kim¹,

Sips²,

Contributors³

2013

Nucl. Fusion

View full text Add to dashboard Cite

Abstract. This paper presents the DYON simulations of the plasma burn-through phase at Joint European Torus (JET) with the ITER-like wall. The main purpose of the study is to validate the simulations with the ITER-like wall, made of beryllium. Without impurities, the burn-through process of a pure deuterium plasma is described using DYON simulations, and the criterion for deuterium burn-through is derived analytically. The plasma burn-through with impurities are simulated using wallsputtering models in the DYON code, which are modified for the ITER-like wall. The wall-sputtering models and the validation against JET data are presented. The impact of the assumed plasma parameters in DYON simulations are discussed by means of parameter scans. As a result, the operation space of prefill gas pressure and toroidal electric field for plasma burn-through in JET is compared to the Townsend avalanche criterion.Physics of plasma burn-through and DYON simulations for the JET ITER-like wall 2

show abstract

Analysis of initial stage of plasma discharge in tokamaks: mathematical model formulation, simulation results, comparison with experiments

Cited by 9 publications

References 2 publications

Runaway electron generation during tokamak start-up

Runaway electron generation during tokamak start-up

Enhancement of plasma burn-through simulation and validation in JET

Physics of plasma burn-through and DYON simulations for the JET ITER-like wall

Contact Info

Product

Resources

About