Speaker
Roberto Bilato
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P1.1070.pdf
Synergies between H-NBI fast-ions and ICRF heating in the non-activated
operational phase of ITER
R. Bilato1 , A.R. Polevoi2 , M. Schneider2 , M. Brambilla1 , E. Fable1 , M. Weiland1 , Ye.O. Kazakov3 ,
E. Lerche3 , A. Loarte2 , J. Ongena3 , S.D. Pinches2 , D. Van Eester3
1 Max-Planck Institut für Plasmaphysik - Germany, EURATOM Ass.
2 ITER Organization, Route de Vinon sur Verdon, CS 90 046, 13067 St Paul-lez-Durance Cedex, France
3 LPP-ERM/KMS, Association Eurofusion-Belgian State, TEC partner, Brussels, Belgium
To access the type-I ELMy H-mode scenarios in ITER during the Pre-fusion Power Operation
2 (PFPO-2) with hydrogen and helium plasmas, it is necessary to operate at reduced confining
magnetic field to exceed the power threshold for the L-H transition [1]. During this operation
phase it is planned the commissioning of the baseline auxiliary power heating, made up of
33 MW of NBI (hydrogen at a maximum injection energy of 870 keV), 20 MW of ECRH
and 20 MW of ICRF (f=40-55 MHz) [2]. Depending on the ICRF frequency and the confining
magnetic field, hydrogen can resonate at its harmonic cyclotron frequency (1st at half field and
2nd at one-third field) with the launched ICRF waves [2]. In particular, the NBI-ICRF synergies
when the NBI species resonates at its 1st harmonic using three-ion scenarios have been recently
observed in JET [3]. Therefore, synergies between fast-protons of NBI heating and ICRF waves
can have an impact on ICRF-heating performances. To investigate these synergies, here, we use
the 2-dimensional full-wave TORIC solver for the wave propagation and absorption of ICRF
waves, and SSFPQL solver for the kinetic equation of the heated species in the simultaneous
presence of NBI sources and ICRF heating. TORIC and SSFPQL are interfaced in such a way
that the coefficients of TORIC wave equation are built directly from the numerical solutions of
SSFPQL [4]. The kinetic equation is solved for all the ion species that can resonate with ICRF
waves. The target plasma is generated with ASTRA transport code with appropriate pedestal [5],
boundary conditions [6], and transport model [7]. As main scan parameters we consider ICRF
frequency and H concentration. As common feature, we find that NBI heating increases the
fraction of ICRF power directly absorbed by hydrogen and substantially broadens the profile of
ICRF power absorbed by hydrogen.
[1] Y. Martin, et al., J. of Physics: Conf. Series 123 (2008) 012033. [2] M. Schneider, et al.,
Proc. 44th EPS Conf. on Plasma Physics, (2017) P5.153. [3] J. Ongena et al., EPJ Web Conf.
157 (2017) 02006. [4] R. Bilato, et al., Nucl. Fusion, 51 (2011) 103034. [5] A.R. Polevoi,
et al, Nucl. Fusion, 57 (2017) 022014. [6] A.S. Kukushkin, Nucl. Fusion, 53 (2013) 123025.
[7] A.R. Polevoi, et al., Proc. 39th EPS Conf. on Plasma Physics, (2012) P4.032.
