JET and COMPASS asymmetrical disruptions

Gerasimov, S.; Abreu, P.; Baruzzo, M.; Дроздов, В.В.; Dvornova, A.; Havlíček, J.; Hender, T. C.; Hronova, O.; Kruezi, U.; Li, X.; Markovič, T.; Pánek, R.; Rubinacci, G.; Tsalas, M.; Ventre, Salvatore; Villone, F.; Zakharov, L.; Contributors, Jet

doi:10.1088/0029-5515/55/11/113006

Cited by 43 publications

(73 citation statements)

References 44 publications

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“…The new ITPA halo current rotation database includes data from five tokamaks: Alcator C-Mod [3], DIII-D [35], ASDEX Upgrade (AUG) [7], NSTX [36], and JET [34,37]. These machines collectively span a wide range of spatial scales and equilibrium parameters so that the scaling of halo current rotation with a variety of machine parameters can be assessed.…”

Section: The Itpa Halo Current Rotation Databasementioning

confidence: 99%

“…Table 1 summarizes the machine, wall material, sensor type, and shot count for each of the seven datasets. Importantly, since disruption mitigation schemes such as massive gas injection (MGI) are known to suppress halo current asymmetries [33,34], only unmitigated disruptions are considered in this study. To ensure that this is the case, information on the triggering of various disruption mitigation systems is also included in the database.…”

Section: The Itpa Halo Current Rotation Databasementioning

confidence: 99%

“…This generates toroidally asymmetric forces that manifest themselves, for example, as strong lateral impulses in large tokamaks such as JET [9,23,25]. Given that toroidal halo current asymmetries are largely ameliorated by disruption mitigation systems such as massive gas injection (MGI) [33,34], we focus in this paper on halo currents generated during unmitigated disruptions.…”

Section: Introductionmentioning

confidence: 99%

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A multi-machine scaling of halo current rotation

et al. 2017

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Halo currents generated during unmitigated tokamak disruptions are known to develop rotating asymmetric features that are of great concern to ITER because they can dynamically amplify the mechanical stresses on the machine. This paper presents a multi-machine analysis of these phenomena. More specifically, data from C-Mod, NSTX, ASDEX Upgrade, DIII-D, and JET are used to develop empirical scalings of three key quantities: (1) the machine-specific minimum current quench time, τ CQ ; (2) the halo current rotation duration, trot; and (3) the average halo current rotation frequency, f h. These data reveal that the normalized rotation duration, trot/τ CQ , and the average rotation velocity, v h , are surprisingly consistent from machine to machine. Furthermore, comparisons between carbon and metal wall machines show that metal walls have minimal impact on the behavior of rotating halo currents. Finally, upon projecting to ITER, the empirical scalings indicate that substantial halo current rotation above f h = 20 Hz is to be expected. More importantly, depending on the projected value of τ CQ in ITER, substantial rotation could also occur in the resonant frequency range of 6-20 Hz. As such, the possibility of damaging halo current rotation during unmitigated disruptions in ITER cannot be ruled out.

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Section: The Itpa Halo Current Rotation Databasementioning

confidence: 99%

Section: The Itpa Halo Current Rotation Databasementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A multi-machine scaling of halo current rotation

et al. 2017

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“…Although it is broadly accepted that the maximum total vertical force (F z ) will be of the order of 80 MN [29,8], the prediction for the horizontal force (F h ) differs by orders of magnitude. Using the maximum values found in JET for F h (∼ 4 MN) [10] and extrapolating with Noll's formula [22], maximal horizontal forces of 40 MN are obtained. Dedicated studies using a source/sink model inspired by JET measurements [26] also find F h ∼ 40MN [7].…”

Section: Introductionmentioning

confidence: 99%

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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“…Recent progress in theoretical understanding of so-called Asymmetric Vertical Displacement Events (AVDE) in tokamaks is related with the theory of Wall Touching Kink Modes and Wall Touching Vertical Magneto-Hydrodynamic Modes (WTKM,WTVM) (Zakharov 2008;Gerasimov at al. 2014;Xiong et al 2015;Gerasimov at al. 2015).…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic thin-wall model for simulations of plasma wall-touching kink and vertical modes

Zakharov¹,

Atanasiu

Lackner

et al. 2015

J. Plasma Phys.

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The understanding of plasma disruptions in tokamaks and predictions of their effects require realistic simulations of electric current excitation in three-dimensional vessel structures by the plasma touching the walls. As discovered at JET in 1996 (Litunovski JET Internal Report contract no. JQ5/11961, 1995; Noll et al., Proceedings of the 19th Symposium on Fusion Technology, Lisbon (ed. C. Varandas & F. Serra), vol. 1, 1996, p. 751. Elsevier) the wall-touching kink modes are frequently excited during vertical displacement events and cause large sideways forces on the vacuum vessel which are difficult to withstand in large tokamaks. In disruptions, the sharing of electric current between the plasma and the wall plays an important role in plasma dynamics and determines the amplitude and localization of the sideways force (Riccardo et al., Nucl. Fusion, vol. 40, 2000, p. 1805; Riccardo & Walker, Plasma Phys. Control. Fusion, vol. 42, 2000, p. 29; Zakharov, Phys. Plasmas, vol. 15, 2008, 062507; Riccardo et al., Nucl. Fusion, vol. 49, 2009, 055012; Bachmann et al., Fusion Engng Des., vol. 86, 2011, pp. 1915–1919). This paper describes a flat triangle representation of the electric circuits of a thin conducting wall of arbitrary three-dimensional geometry. Implemented into the shell simulation code (SHL) and the source sink current code (SSC), this model is suitable for modelling the electric currents excited in the wall inductively and through current sharing with the plasma.

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JET and COMPASS asymmetrical disruptions

Cited by 43 publications

References 44 publications

A multi-machine scaling of halo current rotation

A multi-machine scaling of halo current rotation

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

Electromagnetic thin-wall model for simulations of plasma wall-touching kink and vertical modes

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