Activities per year
Abstract
The main results of an intense vertical displacement event (VDE) modelling activity using the implicit 3D extended MHD code M3D-C1 are presented. A pair of nonlinear 3D simulations are performed using realistic transport coefficients based on the reconstruction of a so-called NSTX frozen VDE where the feedback control was purposely switched off to trigger a vertical instability. The vertical drift phase is solved assuming axisymmetry until the plasma contacts the first wall, at which point the intricate evolution of the plasma, decaying to large extent in force-balance with induced halo/wall currents, is carefully resolved via 3D nonlinear simulations. The faster 2D nonlinear runs allow to assess the sensitivity of the simulations to parameter changes. In the limit of perfectly conducting wall, the expected linear relation between vertical growth rate and wall resistivity is recovered. For intermediate wall resistivities, the halo region contributes to slowing the plasma down, and the characteristic VDE time depends on the choice of halo temperature. The evolution of the current quench and the onset of 3D halo/eddy currents are diagnosed in detail. The 3D simulations highlight a rich structure of toroidal modes, penetrating inwards from edge to core and cascading from high-n to low-n mode numbers. The break-up of flux-surfaces results in a progressive stochastisation of field-lines precipitating the thermalisation of the plasma with the wall. The plasma current then decays rapidly, inducing large currents in the halo region and the wall. Analysis of normal currents flowing in and out of the divertor plate reveals rich time-varying patterns. © 2018 Author(s).
Original language | English |
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Pages (from-to) | 056106 |
Journal | Physics of Plasmas |
Volume | 25 |
Issue number | 5 |
DOIs | |
Publication status | Published - 2 May 2018 |
Externally published | Yes |
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Dive into the research topics of 'Modelling of NSTX hot vertical displacement events using M3D-C1'. Together they form a unique fingerprint.Activities
- 3 Contribution or participation in a conference
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59th Annual Meeting of the APS Division of Plasma Physics
David Pfefferle (Keynote speaker/Invited speaker)
23 Oct 2017 → 27 Oct 2017Activity: Conferences and workshops › Contribution or participation in a conference
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Theory and Simulation of Disruptions Workshop
David Pfefferle (Keynote speaker/Invited speaker)
17 Jul 2017 → 19 Jul 2017Activity: Conferences and workshops › Contribution or participation in a conference
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Sherwood Fusion Theory Conference
David Pfefferle (Participant)
1 May 2017 → 3 May 2017Activity: Conferences and workshops › Contribution or participation in a conference
Research output
- 11 Citations
- 1 Conference presentation/ephemera
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The ins and outs of modelling vertical displacement events
Pfefferlé, D., 24 Oct 2017.Research output: Contribution to conference › Conference presentation/ephemera