TY - JOUR
T1 - Effect of plasma geometry on divertor heat flux spreading
T2 - MONALISA simulations and experimental results from TCV
AU - the EUROfusion MST1 and TCV teams
AU - Gallo, A.
AU - Fedorczak, N.
AU - Maurizio, R.
AU - Theiler, C.
AU - Elmore, S.
AU - Labit, B.
AU - Reimerdes, H.
AU - Nespoli, F.
AU - Ghendrih, P.
AU - Eich, T.
N1 - Publisher Copyright:
© 2016 The Authors
PY - 2017/8
Y1 - 2017/8
N2 - Safe ITER operations will rely on power spreading to keep the peak heat flux within divertor material constraints. A solid understanding and parameterization of heat flux profiles is therefore mandatory. This paper focuses on the impact of plasma geometry on the power decay length (λq) and the spreading factor (S). Numerical heat flux profiles, obtained with the simple SOL transport model MONALISA, agree with theoretical predictions for purely diffusive cylindrical plasmas: λq does not depend on the machine-specific divertor geometry but only on transport parameters and global geometry (a, R, k). A dedicated experiment on TCV was designed to further test this assumption in L-mode plasmas with similar control parameters and upstream shape but different divertor leg length (Zmag = −14, 0, 28 cm). Characterization of OSP q∥ profiles with Langmuir probes and infrared thermography enlightens unexpected behavior with the divertor leg length: λq increases, while S shows no clear trend. These findings suggest that the link between heat flux profiles, plasma geometry and transport is currently not fully understood.
AB - Safe ITER operations will rely on power spreading to keep the peak heat flux within divertor material constraints. A solid understanding and parameterization of heat flux profiles is therefore mandatory. This paper focuses on the impact of plasma geometry on the power decay length (λq) and the spreading factor (S). Numerical heat flux profiles, obtained with the simple SOL transport model MONALISA, agree with theoretical predictions for purely diffusive cylindrical plasmas: λq does not depend on the machine-specific divertor geometry but only on transport parameters and global geometry (a, R, k). A dedicated experiment on TCV was designed to further test this assumption in L-mode plasmas with similar control parameters and upstream shape but different divertor leg length (Zmag = −14, 0, 28 cm). Characterization of OSP q∥ profiles with Langmuir probes and infrared thermography enlightens unexpected behavior with the divertor leg length: λq increases, while S shows no clear trend. These findings suggest that the link between heat flux profiles, plasma geometry and transport is currently not fully understood.
UR - https://www.scopus.com/pages/publications/85005777596
UR - https://www.scopus.com/inward/citedby.url?scp=85005777596&partnerID=8YFLogxK
U2 - 10.1016/j.nme.2016.10.003
DO - 10.1016/j.nme.2016.10.003
M3 - Article
AN - SCOPUS:85005777596
SN - 2352-1791
VL - 12
SP - 893
EP - 898
JO - Nuclear Materials and Energy
JF - Nuclear Materials and Energy
ER -