Speaker
Timofey Kormilitsyn
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.1005.pdf
Assessment of the Fast Particle Spectra for Tangential Spectrometer for
H/He and DT ITER Operation
T.M. Kormilitsyn1, A.R. Polevoi2, L. Bertalot2, M.I. Mironov3, V. Krasilnikov2, A. Serikov4, R.
Barnsley2, Yu. A. Kashchuk5, A. Loarte2, S.D. Pinches2, M. Walsh2
1
Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141700, Russia
2
ITER Organization, Route de Vinon sur Verdon, CS 90 046, 13067 St Paul-lez-Durance Cedex, France
3
Ioffe Institute, St. Petersburg 194021, Russia, 4Karlsruhe Institute of Technology, 76344
Eggenstein-Leopoldshafen, Germany, 5Project Center ITER, Moscow, Russia
The study of fast ion behaviour in reactor conditions is among the major goals of the ITER
project. Additional heating by NBI and ICH creates population of suprathermal ions with an
anisotropic distribution in velocity space. The energy spectrum measurements of CX neutrals
and neutrons made by the Tangential Neutron Spectrometer (TNS) contribute to the
reconstruction of the fast ions’ distribution function in combination with the radial
measurements by the NPA, RNC, and HRNS diagnostics. It will help determine the
consequences of instabilities which cause the redistribution of fast ions in the plasma and to
the assessment of their impact on plasma heating and current drive. Assessing the capabilities
of diagnostics at different phases of ITER operation is an essential part of ITER research
planning. Simulations of the signals that will be measured at different phases of ITER
operation require computational tools, so called synthetic diagnostics (SD), with realistic
geometry and parameters corresponding to the ITER diagnostic design. To assess the
accuracy and resolution of the measurements of the TNS in all ITER scenarios we have
developed a TNS SD compatible with the ITER IMAS suite of codes. The module developed
enables simulation of the anisotropic spectra of the charge-exchange (CX) neutrals and
neutrons originated from interactions between suprathermal and thermal ions together with
the background spectra. Simulations of realistic signals require appropriate approximations
for the processes which produce the main and background signals. In our simulations the
distribution of the suprathermal ions is calculated by solving the 3D Fokker-Plank equation
for the different scenarios foreseen in the ITER research plan. This includes the pre-DT and
DT phases of ITER operation with different orientations of the NBI as foreseen in the ITER
design. Simulations of the spectrum of the CX neutrals are based on the DOUBLE-MC code
extended to simulate anisotropic sources and neutrons. Background spectra at the location of
the TNS detectors for neutrons were calculated on the basis of a parameterisation of the
MCNP simulations with realistic ITER geometry and features of the machine components.
Assessment of the CX neutrals and DT neutrons spectra is carried out for H-NBI during the
pre-DT phase and D-NBI heated baseline DT scenarios. The impact of the fast particle
distribution on the spectra is studied.
