O. Vallhagen I. Pusztai P. Helander S. L. Newton T. Fülöp
Pellet injection is used for fuelling and controlling discharges in tokamaks, and it is foreseen in ITER. During pellet injection, a movement of the ablated material towards the low- field side (or outward major radius direction) occurs because of the inhomogeneity of the magnetic field. Due to the complexity of the theoretical models, computer co…
PreprintO. Myatra D. Moulton B. Dudson S. Newton B. Lipschultz K. Verhaegh A. Fil
The role of ion-molecule elastic collisions (specifically D+−D2 collisions) in strongly detached divertor conditions has been studied in the MAST-U Super-X configuration using SOLPS-ITER. Two strongly detached steady state solutions, one obtained through a main-ion (D2) fuelling scan and the other through an impurity (N) seeding scan at fixed fue…
PreprintR. T. Osawa D. Moulton S. L. Newton S. Henderson B. Lipschultz A. Hudoba
To mitigate the issue of plasma exhaust in reactor scale tight aspect ratio tokamaks such as STEP (Spherical Tokamak for Energy Production), a double-null (DN) configuration is thought to be advantageous over a single-null (SN) configuration. However, practical control of the plasma vertical stability will likely lead to an oscillation around th…
PreprintO. Vallhagen I. Pusztai M. Hoppe S. L. Newton T. Fülöp
An effective disruption mitigation system in a tokamak reactor should limit the exposure of the wall to localized heat losses and to the impact of high current runaway electron beams, and avoid excessive forces on the structure. We evaluate with respect to these aspects a two-stage deuterium-neon shattered pellet injection in an ITER-like plasma, u…
Preprint PublishedE. Berger I. Pusztai S.L. Newton M. Hoppe O. Vallhagen A. Fil T. Fülöp
Understanding generation and mitigation of runaway electrons in disruptions is important for the safe operation of future tokamaks. In this paper we investigate runaway dynamics in reactor-scale spherical tokamaks. We study both the severity of runaway generation during unmitigated disruptions, as well as the effect that typical mitigation schem…
Preprint PublishedS. Mijin F. Militello S. Newton J.T. Omotani R.J. Kingham
We present the first parallel electron transport results obtained using the newly developed 1D transport code SOL-KiT. In order to properly predict divertor heat loads it is of key importance to develop a thorough understanding of discrepancies between different parallel transport modelling approaches. With the capability to self-consistently sw…
Preprint PublishedC J Ham A Bokshi D Brunetti G Bustos Ramirez B Chapman J W Connor D Dickinson A R Field J P Graves T Kiviniemi S Leerink B McMillan S Newton S Pamela C M Roach S Saarelma J Simpson S F Smith P Strand A Virtanen the JET Contributors*
The pedestal plays an important role in determining the confinement in tokamak H-mode plasmas. However, the steep pressure gradients in this transport barrier also lead to edge localized modes (ELMs) [1]. There is good understanding of the pedestal in type I ELM regimes [2], however, type I ELMs are known to damage plasma facing components and f…
Preprint PublishedB. Dudson S. L. Newton J. T. Omotani J. Birch
Drift-reduced MHD models are widely used to study magnetised plasma phenomena, in particular for magnetically confined fusion applications, as well as in solar and astrophysical research. This letter discusses the choice of Ohm’s law in these models, the resulting dispersion relations for the dynamics parallel to the magnetic field, and the i…
Preprint PublishedD. Galassi C. Theiler T. Body F. Manke P. Micheletti J. Omotani M. Wiesenberger M. Baquero-Ruiz I. Furno M. Giacomin E. Laribi F. Militello P. Ricci A. Stegmeir P. Tamain H. Bufferand G. Ciraolo H. De Oliveira A. F. Fasoli V. Naulin S. L. Newton N. Offeddu D. Sales Oliveira E. Serre N. Vianello
Transport processes around the magnetic X-point of tokamaks, such as turbulence and mean-field drifts, are scarcely understood and difficult to investigate in experiments. In this paper, we explore the dynamics in a newly developed X-point scenario on the basic toroidal plasma device TORPEX and use it to validate plasma edge turbulence codes. In-si…
Preprint PublishedI. Svenningsson O. Embreus M. Hoppe S. L. Newton T. Fülöp
Runaway electron populations seeded from the hot-tail generated by the rapid cooling in plasma terminating disruptions are a serious concern for next-step tokamak devices such as ITER. Here, we present a comprehensive treatment of the thermal quench, including the superthermal electron dynamics, heat and particle transport, atomic physics, and radi…
Preprint Published