Global forces on the COMPASS-U wall during plasma disruptions

Yanovskiy, Vadim; Isernia, N.; Pustovitov, V. D.; Scalera, Valentino; Villone, F.; Hromádka, Jakub; Imríšek, M.; Havlíček, J.; Hron, M.; Pánek, R.

doi:10.1088/1741-4326/ac1545

Cited by 13 publications

(7 citation statements)

References 25 publications

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“…Therefore, for time scales much shorter than τ w , the vessel forces remain small (F ≈ 0) since B remains approximately unchanged outside the wall (as observed in [15]). However, as it is deduced from (1) and it is shown in this paper, the force can arise after the field penetrates the wall even in the absence of plasma currents (this was also observed in [16]). Thus, we stress the importance of running these simulations for several τ w , even when the plasma current has already decayed.…”

Section: Introductionsupporting

confidence: 74%

Non-axisymmetric MHD simulations of the current quench phase of ITER mitigated disruptions

Artola¹,

Loarte²,

Hoelzl³

et al. 2022

Nucl. Fusion

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Non-axisymmetric simulations of the current quench phase of ITER disruptions are key to predict asymmetric forces acting into the ITER wall. We present for the first time such simulations for ITER mitigated disruptions at realistic Lundquist numbers. For these strongly mitigated disruptions, we find that the edge safety factor remains above 2 and the maximal integral horizontal forces remain below 1 MN. The maximal integral vertical force is found to be 13 MN and arises in a time scale given by the resistive wall time as expected from theoretical considerations. In this respect, the vertical force arises after the plasma current has completely decayed, showing the importance of continuing the simulations also in the absence of plasma current. We conclude that the horizontal wall force rotation is not a concern for these strongly mitigated disruptions in ITER, since when the wall forces form, there are no remaining sources of rotation.

show abstract

Section: Introductionsupporting

confidence: 74%

Non-axisymmetric MHD simulations of the current quench phase of ITER mitigated disruptions

Artola¹,

Loarte²,

Hoelzl³

et al. 2022

Nucl. Fusion

View full text Add to dashboard Cite

show abstract

“…Therefore, for time scales much shorter than τ w , the vessel forces remain small (F ≈ 0) since B remains approximately unchanged outside the wall. However, as it is deduced from (1) and it is shown in this paper, the force can arise after the field penetrates the wall even in the absence of plasma currents (this was also observed in [31]). This fact has been largely ignored in the literature of 3D MHD disruptions and 3D simulations are typically not continued after the plasma current vanishes.…”

Section: Introductionsupporting

confidence: 74%

Complete 3D MHD simulations of the current quench phase of ITER mitigated disruptions

Artola¹,

Loarte²,

Hoelzl³

et al. 2021

Preprint

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Complete 3D simulations of the current quench phase of ITER disruptions are key to predict asymmetric forces acting into the ITER wall. We present for the first time such simulations for ITER mitigated disruptions at realistic Lundquist numbers. For these strongly mitigated disruptions, we find that the safety factor remains above 2 and the maximal integral horizontal forces remain below 1 MN. The maximal integral vertical force is found to be 13 MN and arises in a time scale given by the resistive wall time as expected from theoretical considerations. In this respect, the vertical force arises after the plasma current has completely decayed, showing the importance of continuing the simulations also in the absence of plasma current. We conclude that the horizontal wall force rotation is not a concern for these strongly mitigated disruptions in ITER, since when the wall forces form, there are no remaining sources of rotation.

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“…Recently, the final COMPASS experimental campaign was completed, the COMPASS tokamak was shut down in August 2021, and its disassembly has started. In parallel, preparations for the construction of the COMPASS Upgrade tokamak [62] proceeded through the final design phase and the COMPASS Upgrade related analysis, like the modelling of disruption forces [63] and of the NBI heating [64] were also presented at the 28th IAEA FEC. Therefore, the COMPASS experimental hall and related infrastructure is being evacuated at present and the experimental hall will modified to accommodate the new COMPASS Upgrade tokamak.…”

Section: Discussionmentioning

confidence: 99%

Overview of the COMPASS results ^*

et al. 2022

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COMPASS addressed several physical processes that may explain the behaviour of important phenomena. This paper presents results related to main fields of COMPASS research obtained in the recent two years, including studies of turbulence, L-H transition, plasma material interaction, runaway electron, and disruption physics:  Tomographic reconstruction of the edge/SOL turbulence observed by a fast visible camera allowed to visualize turbulent structures without perturbing the plasma. Dependence of the power threshold on the X-point height was studied and related role of radial electric field in the edge/SOL plasma was identified. The effect of high-field-side error fields on the L-H transition was investigated in order to assess the influence of the central solenoid misalignment and the possibility to compensate these error fields by low-field-side coils. Results of fast measurements of electron temperature during ELMs show the ELM peak values at the divertor are around 80% of the initial temperature at the pedestal. Liquid metals were used for the first time as plasma facing material in ELMy H-mode in the tokamak divertor. Good power handling capability was observed for heat fluxes up to 12 MW/m 2 and no direct droplet ejection was observed.  Partial detachment regime was achieved by impurity seeding in the divertor. The evolution of the heat flux footprint at the outer target was studied.  Runaway electrons were studied using new unique systems -impact calorimetry, carbon pellet injection technique, wide variety of magnetic perturbations. Radial feedback control was imposed on the beam.  Forces during plasma disruptions were monitored by a number of new diagnostics for vacuum vessel motion in order to contribute to the scaling laws of sideways disruption forces for ITER. Current flows towards the divertor tiles, incl. possible short-circuiting through PFCs, were investigated during the VDE experiments. The results support ATEC model and improve understanding of disruption loads.

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Global forces on the COMPASS-U wall during plasma disruptions

Cited by 13 publications

References 25 publications

Non-axisymmetric MHD simulations of the current quench phase of ITER mitigated disruptions

Non-axisymmetric MHD simulations of the current quench phase of ITER mitigated disruptions

Complete 3D MHD simulations of the current quench phase of ITER mitigated disruptions

Overview of the COMPASS results ^*

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Global forces on the COMPASS-U wall during plasma disruptions

Cited by 13 publications

References 25 publications

Non-axisymmetric MHD simulations of the current quench phase of ITER mitigated disruptions

Non-axisymmetric MHD simulations of the current quench phase of ITER mitigated disruptions

Complete 3D MHD simulations of the current quench phase of ITER mitigated disruptions

Overview of the COMPASS results *

Contact Info

Product

Resources

About

Overview of the COMPASS results ^*