UKAEA Papers

"Reduced-model scrape-off layer turbulence (nSOLT) simulations comparing three fueling scenarios: pellet injection (core), divertor recycling (edge), and neutral puffing (SOL)"

• D. Russel
• J. Myra
• F. Militello
• D. Moulton

The 2D scrape-off-layer turbulence code (nSOLT) includes 1D Boltzmann neutral-plasma interactions, a model of divertor recycling (introduced here), and a fixed source of plasma concentrated at the core-side boundary. 1) Neutral injection in the far-SOL is accomplished by specifying the density of Franck-Condon distributed neutrals streaming in from…

"Understanding the effects of super-X divertor configuration on optimizing the operational space in DEMO"

• L. Xiang
• F. Militello
• D. Moulton
• F. Subba
• L. Aho-Mantila
• D. Coster
• M. Wensing
• T. Lunt
• M. Wischmeier
• H. Reimerdes

The SOLPS-ITER simulations of European DEMO reactor, with 450 MW of power to be exhausted, show an increased operational space compared to the conventional single-null configuration. Using a reduced model with fluid neutrals and bundled impurities, we assessed the existence and the boundaries of operational space for DEMO with the conventional sing…

"Recent modelling of long-legged divertor configurations"

• D. Moulton
• A. Fil
• O. Myatra
• B. Lipschultz
• B. Dudson

The paper reviews recent SOLPS modelling of long-legged divertors carried out by UKAEA and the University of York. The required upstream density required for detachment is predicted to scale inversely with the total flux expansion of the divertor, but experimentally this was not found to be the case on TCV. Interpretative SOLPS-ITER modelling sugge…

"A novel hydrogenic spectroscopic technique for inferring the role of plasma-molecule interaction on power and particle balance during detached conditions"

• K. Verhaegh
• B. Lipschultz
• C. Bowman
• B.P. Duval
• U. Fantz
• A. Fil
• D. Moulton
• O. Myatra
• D. Wünderlich
• F. Federici
• D.S. Gahle
• J.R. Harrison
• A. Perek
• M. Wensing

Detachment, an important mechanism for reducing target heat deposition, is achieved through reductions in power, particle and momentum; which are induced through plasma-atom and plasma-molecule interactions. Experimental research in how those reactions precisely contribute to detachment is limited. Both plasma-atom as well as plasma-molecule intera…

"Preliminary analysis of alternative divertors for DEMO"

• F. Militello
• L. Aho-Mantila
• R. Ambrosino
• T. Body
• H. Bufferand
• G. Calabro’
• G. Ciraolo
• D. Coster
• G. Di Gironimo
• P. Fanelli
• N. Fedorczak
• A. Herrmann
• P. Innocente
• R. Kembleton
• J. Lilburne
• T. Lunt
• D. Marzullo
• S. Merriman
• D. Moulton
• A. Nielsen
• J. Omotani
• G. Ramogida
• H. Reimerdes
• M. Reinhart
• P. Ricci
• F. Riva
• A. Stegmeir
• F. Subba
• W. Suttrop
• P. Tamain
• M. Teschke
• A. Thrysoe
• W. Treutterer
• S. Varoutis
• M. Wensing
• A. Wilde
• M. Wischmeier
• L.Y. Xiang

A thorough physics and engineering analysis of alternative divertor configurations is carried out by examining benefits and problems by comparing the baseline single null solution with a Snowflake, an X- and a Super-X divertor. It is observed that alternative configurations can provide margin and resilience against large power fluctuations, but the…

"An examination of the Neutral penetration model 1/ne,ped scaling for its validity of spatially varying neutral sources"

• J. Simpson
• D. Moulton
• C. Giroud
• F. Casson
• M. Groth
• A. Chankin
• L. Horvath
• D. S. Gahle
• F. Kochl

EDGE2D-EIRENE simulations show that for a H-mode JET discharge (92168) the dominant atomic neutral deuterium source at the separatrix originates from the inner divertor target. Within JETTO-EIRENE neutral sources are placed at the X-point and outer midplane (OMP). For fixed electron and ion temperature, transport and neutral temperature it is obser…

"Comparison between SOLPS-4.3 and the Lengyel Model for ITER baseline neon-seeded plasmas"

• D. Moulton
• P. C. Stangeby
• X. Bonnin
• R. A. Pitts

If correct, the Lengyel model offers a simple and powerful tool to predict the conditions required for detachment onset in future fusion reactors. We assess its validity against a comprehensive SOLPS-4.3 simulation database of ITER baseline (Q = 10) neon-seeded plasmas (Pacher et al 2015 J. Nucl. Mater. 463 591). In absolute terms, the Lengyel Mode…

"Upstream separatrix temperature dependence in EDGE2D-EIRENE for JET H-mode plasmas"

• J. Simpson
• D. Moulton
• C. Giroud
• D. Harting
• G. Corrigan
• M. Groth
• JET Contributors

EDGE2D-EIRENE simulations of upstream density and radiative power scans in JET H-mode type plasmas in vertical target predict a linear relationship between the electron and ion temperatures, and power across the separatrix. This is in contradiction to the two-point model equations which states that the upstream temperature scales at the po…

"Optimization of JET-DT and ITER operation by developing an understanding of the role of low-Z impurity on the H-mode pedestal"

• C. Giroud
• N. Aiba
• F. Militello
• C. Challis
• A. Chankin
• B. Lomanowski
• D. Hatch
• J. Harrison
• D. Frigione
• D. Moulton
• S. Pamela
• F. Parra
• J. Parisi
• I. Putzai
• D. Refy
• S. Saarelma
• C. Stavrou
• B. Tal
• E. Belonohy
• S. Brezinsek
• S. Buller
• C. Bowman
• E. Delabie
• A. Field
• J. Fontdecaba
• A. Huber
• A. Meigs
• S. Menmuir
• J. Simpson
• JET Contributors

"Simulations of edge localised mode instabilities in MAST-U Super-X tokamak plasmas"

• S.F. Smith
• S.J.P. Pamela
• A. Fil
• M. Hoelzl
• G.T.A. Huijsmans
• A. Kirk
• D. Moulton
• O. Myatra
• A.J. Thornton
• H.R. Wilson

ELM simulations for the MAST-U Super-X tokamak have been obtained, using the JOREK code. The JOREK visco-resistive MHD model has been used to obtain comparisons of divertor configurations. The simulations show a factor 10 decrease in the peak heat flux to the outer target of the Super-X in comparison to a conventional divertor configuration. A roll…