Requirements for pellet injection in ITER scenarios with enhanced particle confinement

Abstract

Requirements for pellet injection parameters for plasma fuelling are assessed for ITER scenarios with enhanced particle confinement. The assessment is based on the integrated transport simulations including models of pedestal transport, reduction of helium transport and boundary conditions compatible with SOL/divertor simulations. The requirements for pellet injection for the inductive H-mode scenario (H H98y,2 = 1) are reconsidered taking account of a possible reduction of the particle loss obtained in some experiments at low collisionalities. The assessment of fuelling requirements is carried out for the hybrid and steady state scenarios with enhanced confinement with H H98y,2 > 1. A robustness of plasma performance to the variation of particle transport is demonstrated. A new type of steady state (SS) scenario is considered with neutral beam current drive (NBCD) and electron cyclotron current drive (ECCD) instead of lower hybrid current drive (LHCD) to extend the range of stable operation and to avoid the reduction of the edge LHCD efficiency caused by pellet injection.

Comprehensive evaluation of the linear stability of Alfvén eigenmodes driven by alpha particles in an ITER baseline scenario

“…Kinetic profiles from ASTRA simulations [5,11] for two variants of the 15 MA ITER baseline scenario. Compared with the LoPed scenario variant (left), HiPed (right) is characterised by higher pedestal temperatures and lower temperatures at the plasma core (dashed lines), which results in lower densities of the main fusion products, namely alpha particles and He ashes.…”

“…The two variants of the ITER scenario that are analysed here have been produced by ASTRA transport simulations [5,11]. In both variants the plasma current is I p = 15 MA, the toroidal magnetic field is B 0 = 5.3 T, and the plasma major and minor radii are R 0 = 6.2 m and a = 2 m, respectively.…”

“…In this article the stability of AEs is systematically addressed for the 15 MA ELMy H-mode ITER baseline scenario [5,6,7,8] making use of a recently introduced framework [8] that is based on the hybrid MHD drift-kinetic code CASTOR-K [9,10], which is the key element in our suite of numerical codes. Growth rates are computed systematically for all possible eigenmodes taking into account the alpha-particle drive, the Landau damping due to the DT …”

The 2008 Public Release of the International Multi-tokamak Confinement Profile Database

“…Such calculations predict that: core fuelling from edge neutrals saturates at a low level S DT,core < 10 22 atoms/s, n ped e ∼ 3 − 4 × 10 19 m −3 , T ped e ∼ 200eV, the He atomic influx is 50% of the outflux, fusion power P fus = 400 − 500MW, and P loss < 100 − 110MW. Inductive baseline reference scenarios were calculated with ASTRA, using B2-Eirene data for edge fuelling and with sufficient pellet core fuelling to reach the design density [170]. These are included in PR08 discharges #10020202 and #10020203.…”

ECE for NTM control on ITER

“…In this paper, the capabilities of Electron Cyclotron Emission (ECE) radiometry for an NTM control loop, which needs to satisfy the accuracy and latency constraints, are assessed for a standard burning H-mode ITER scenario 2 plasma and ECE measured through either the equatorial port plug and via the line-of-sight of ECCD. [5][6] [7] 2 Simulation set-up…”