Optimisation and assessment of theoretical impurity line power coefficients relevant to ITER and DEMO

TY - JOUR

T1 - Optimisation and assessment of theoretical impurity line power coefficients relevant to ITER and DEMO

AU - Henderson, S S

AU - Bluteau, M

AU - Foster, A

AU - Giunta, A

AU - O'Mullane, M G

AU - Pütterich, T

AU - Summers, H P

N1 - This is an author-created, un-copyedited version of an article published in Plasma Physics and Controlled Fusion. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1361-6587/aa6273.

PY - 2017/3/21

Y1 - 2017/3/21

N2 - Total radiated line power coefficients for ions of medium to heavy weight elements, called PLT coefficients in the Atomic Data and analysis Structure (ADAS), have been improved by algorithmically optimising the selection of configuration sets that underpin the calculation to include the most important radiating transitions driven by both the ground and metastable configurations and to establish and limit the error of truncation. The optimised calculations typically differ from Pütterich by 20 − 30% with truncation error ≲5%. Further appraisal of error due to atomic level bundling, atomic structure and collision strength calculation methods has been carried out. It is shown that bundling to configurations is accurate to ≲10% for all ions except those with closed-shell ground configurations which give errors up to a factor 2−3. For near neutral, closed-shell ions, plane-wave Born collision strength calculations, which omit spin-change, give substantial error in comparison with distorted-wave calculations of PLT. For highly charged ions, spin-system breakdown reduces the error in the PLT markedly, typically ≲10%. The error introduced by the atomic structure codes used here, autostructure and the cowan code, is probably limited to ≲30%.

AB - Total radiated line power coefficients for ions of medium to heavy weight elements, called PLT coefficients in the Atomic Data and analysis Structure (ADAS), have been improved by algorithmically optimising the selection of configuration sets that underpin the calculation to include the most important radiating transitions driven by both the ground and metastable configurations and to establish and limit the error of truncation. The optimised calculations typically differ from Pütterich by 20 − 30% with truncation error ≲5%. Further appraisal of error due to atomic level bundling, atomic structure and collision strength calculation methods has been carried out. It is shown that bundling to configurations is accurate to ≲10% for all ions except those with closed-shell ground configurations which give errors up to a factor 2−3. For near neutral, closed-shell ions, plane-wave Born collision strength calculations, which omit spin-change, give substantial error in comparison with distorted-wave calculations of PLT. For highly charged ions, spin-system breakdown reduces the error in the PLT markedly, typically ≲10%. The error introduced by the atomic structure codes used here, autostructure and the cowan code, is probably limited to ≲30%.

KW - total radiated line power coefficients

KW - error

KW - atomic level bundling

KW - atomic structure

KW - collision strength

KW - electron configuration sets

KW - cooling factor

UR - http://iopscience.iop.org/journal/0741-3335

U2 - 10.1088/1361-6587/aa6273

DO - 10.1088/1361-6587/aa6273

M3 - Article

VL - 59

SP - 1

EP - 8

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

SN - 0741-3335

IS - 5

M1 - 055010

ER -