Comparison of fusion alpha performance in JET advanced scenario and H-mode plasmas

Asunta, O.; Kurki-Suonio, T.; Tala, T.; Sipilä, Seppo; Salomaa, Rainer; Contributors, Jet‐Efda

doi:10.1088/0741-3335/50/12/125008

Cited by 2 publications

(2 citation statements)

References 18 publications

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“…The ASCOT code has been used extensively to simulate fast-ion behaviour in a large number of tokamak experiments including DIII-D (Kramer et al 2013b), JET (Fundamenski et al 2002), (Asunta et al 2008) and AUG (Asunta et al 2012). ASCOT has also been used to predict alpha losses for ITER for various plasma scenarios (Kurki-Suonio et al 2009 and in the presence of MHD (Kurki-Suonio et al 2011;Snicker et al 2013).…”

Section: Numerical Simulation Toolsmentioning

confidence: 99%

Fast-ion physics in SPARC

et al. 2020

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Potential loss of energetic ions including alphas and radio-frequency tail ions due to classical orbit effects and magnetohydrodynamic instabilities (MHD) are central physics issues in the design and experimental physics programme of the SPARC tokamak. The expected loss of fusion alpha power due to ripple-induced transport is computed for the SPARC tokamak design by the ASCOT and SPIRAL orbit-simulation codes, to assess the expected surface heating of plasma-facing components. We find good agreement between the ASCOT and SPIRAL simulation results not only in integrated quantities (fraction of alpha power loss) but also in the spatial, temporal and pitch-angle dependence of the losses. If the toroidal field (TF) coils are well-aligned, the SPARC edge ripple is small (0.15–0.30 %), the computed ripple-induced alpha power loss is small ( ${\sim } 0.25\,\%$ ) and the corresponding peak surface power density is acceptable ( $244\ \textrm{kW}\ \textrm {m}^{-2}$ ). However, the ripple and ripple-induced losses increase strongly if the TF coils are assumed to suffer increasing magnitudes of misalignment. Surface heat loads may become problematic if the TF coil misalignment approaches the centimetre level. Ripple-induced losses of the energetic ion tail driven by ion cyclotron range of frequency (ICRF) heating are not expected to generate significant wall or limiter heating in the nominal SPARC plasma scenario. Because the expected classical fast-ion losses are small, SPARC will be able to observe and study fast-ion redistribution due to MHD including sawteeth and Alfvén eigenmodes (AEs). SPARC's parameter space for AE physics even at moderate $Q$ is shown to reasonably overlap that of the demonstration power plant ARC (Sorbom et al., Fusion Engng Des., vol. 100, 2015, p. 378), and thus measurements of AE mode amplitude, spectrum and associated fast-ion transport in SPARC would provide relevant guidance about AE behaviour expected in ARC.

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Section: Numerical Simulation Toolsmentioning

confidence: 99%

Fast-ion physics in SPARC

et al. 2020

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“…Furthermore a dedicated benchmark between ASCOT and the similar Japanese code F3D-OFMC has been performed as part of an ITER task [13]. ASCOT has also been validated against experiments at ASDEX Upgrade [14] and JET [15].…”

Section: The Ascot Simulationsmentioning

confidence: 99%

ASCOT simulations of fast ion power loads to the plasma-facing components in ITER

Kurki-Suonio

Asunta

Hellsten³

et al. 2009

Nucl. Fusion

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The wall loads due to fusion alphas as well as neutral beam injection- and ICRF-generated fast ions were simulated for ITER reference scenario-2 and scenario-4 including the effects of ferritic inserts (FIs), test blanket modules (TBMs), and 3D wall with two limiter structures. The simulations were carried out using the Monte Carlo guiding-centre orbit-following code ASCOT. The FIs were found very effective in ameliorating the detrimental effects of the toroidal ripple: the fast ion wall loads are reduced practically to their negligible axisymmetric level. The thermonuclear alpha particles overwhelmingly dominate the wall power flux. In scenario-4 practically all the power goes to the limiters, while in scenario-2 the load is fairly evenly divided between the divertor and the limiter, with hardly any power flux to other components in the first wall. This is opposite to earlier results, where hot spots were observed with 2D wall (Tobita et al 2003 Fusion Eng. Des. 65 561–8). In contrast, uncompensated ripple leads to unacceptable peak power fluxes of 0.5 MW m−2 in scenario-2 and 1 MW m−2 in scenario-4, with practically all power hitting the limiters and substantial flux arriving even at the unprotected first wall components. The local TBM structures were found to perturb the magnetic field structure globally and lead to increased wall loads. However, the TBM simulation results overestimate the TBM contribution due to an over-simplification in the vacuum field. Therefore the TBM results should be considered as an upper limit.

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Comparison of fusion alpha performance in JET advanced scenario and H-mode plasmas

Cited by 2 publications

References 18 publications

Fast-ion physics in SPARC

Fast-ion physics in SPARC

ASCOT simulations of fast ion power loads to the plasma-facing components in ITER

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