O. 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…
PreprintM. Fitzgerald R. Dumont D. Keeling J. Mailloux S. Sharapov M. Dreval A. Figueiredo R. Coelho J. Ferreira P. Rodrigues F. Nabais D. Borba Ž. Štancar G. Szepesi R.A. Tinguely N Fil P.G. Puglia H.J.C. Oliver V. Kiptily M. Baruzzo M. Lennholm P. Siren J. Garcia C.F. Maggi
A toroidal Alfven eigenmode (TAE) has been observed driven by alpha particles in the Joint European Torus (JET). The observation was made in dedicated deuterium-tritium experiments where radio-frequency (RF) heating was absent, in the so-called “afterglow” period when neutral beam heating was removed. Agreement with reduced and perturbative mod…
PreprintJ.F. Rivero-Rodriguez S. Sharapov K. McClements M. Garcia-Muñoz N. Crocker M. Dreval D. Dunai N. Fil M. Fitzgerald J. Galdon-Quiroga C. Michael D. Ryan L. Velarde the MAST-U Team
Due to their relatively higher Vbeam/VAlvén ratio, spherical tokamaks are ideal to investigate high-frequency modes such as Compressional Alfvén Eigenmodes (CAEs) and Global Alfvén Eigenmodes (GAEs), and so they have been previously studied in MAST [1, 2]. Besides, the recently installed scintillator-based Fast-Ion Loss …
PreprintK. Verhaegh A.C. Williams D. Moulton B. Lipschultz B.P. Duval O. Février A. Fil J. R. Harrison N. Osborne H. Reimerdes C. Theiler
Divertor detachment requires plasma-neutral interactions which dissipate momentum, power and particles simultaneously. Plasma-molecular interactions can result in molecular ions which react with the plasma. This can contribute to detachment through molecular activated recombination (MAR) and molecular activated dissociation (MAD), both of which cre…
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 PublishedK. Verhaegh B. Lipschultz J.R. Harrison N. Osborne A. Williams P Ryan J. Allcock J. Clark F. Federici B. Kool T. Wijkamp A. Fil D. Moulton O. Myatra A. Thornton T.O.S.J. Bosman C. Bowman B. Duval S. Henderson R. Scannell the MAST Upgrade team the EuroFusion MST1 team
In this paper we a first qualitative analysis of the atomic and molecular processes at play during detachment in the MAST-U Super-X divertor, using divertor spectroscopy data. Our analysis indicates a wide operational regime of detachment of the MAST-U super-X divertor, which can be roughly separated in four phases: 1) The ionisation front detac…
PreprintA. Fil B. Lipschultz D. Moulton A. Thornton B. D. Dudson O. Myatra K. Verhaegh the EUROFusion WPTE team
MAST-U has recently started operating with a Super-X divertor, designed to increase total flux expansion and neutral trapping, both predicted through simple analytic models and SOLPS calculations to reduce the plasma and impurity density detachment thresholds. In this study, utilising the SOLPS-ITER code, we are quantifying the possible gain allowe…
Preprint PublishedS.F. Smith S.J.P. Pamela A. Fil M. Hölzl G.T.A. Huijsmans A. Kirk D. Moulton O. Myatra A.J. Thornton H.R. Wilson
The high heat fluxes to the divertor during edge localised mode (ELM) instabilities have to be reduced for a sustainable future tokamak reactor. A solution to reduce the heat fluxes could be the Super-X divertor, this divertor configuration will be tested on MAST-U. ELM simulations for MAST-U Super-X tokamak plasmas have been obtained, using JOR…
PreprintK. Verhaegh B. Lipschultz J.R. Harrison B.P. Duval A. Fil D.S. Gahle D. Moulton O. Myatra A. Perek S. Henderson C. Theiler A. Thornton M. Wensing
This paper shows experimental results from the TCV tokamak that indicate plasma-molecule interactions involving D+2 and possibly D− play an important role as sinks of energy (through hydrogenic radiation as well as dissociation) and particles during divertor detachment if low target temperatures (< 3 eV) are achieved. Bot…
Preprint PublishedKevin Verhaegh Basil Duval Ben Dudson Alex Fil Olivier Février Daljeet Gahle James Harrison Omkar Myatra Artur Perek Christian Theiler Mirko Wensing
In this work we provide experimental insights into the impact of plasma-molecule interactions on divertor detachment by applying new spectroscopic analysis techniques to the hydrogen Balmer line series to investigate how both atom and plasma-molecule interactions impact particle balance. Our analysis on a representative L-mode TCV density ramp dis…
Preprint Published