Simulating energetic particle losses in JET plasmas with a reverse integration biasing scheme

Bonofiglo, P. J.; Podestà, M.; White, R. B.; Kiptily, V.; Goloborod'ko, V. T.; Gorelenkov, N. N.; Vallar, M.; Cecil, F. E.; Giroud, C.; Brezinsek, S.

doi:10.1088/1741-4326/ac3f4a

Cited by 5 publications

(11 citation statements)

References 51 publications

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“…This implies the sawtooth induced transport predominantly affects the beam-born population but only mildly, so that the resulting losses are minimal compared to the prolonged kink induced losses. The high energy PMT shows coherent losses with the saturated kink mode visible in figure 8 of reference [6]. No higher frequency mode activity was observed to account for any additional transport.…”

Section: Experimental Scenariomentioning

confidence: 87%

“…The discharge presents reliable loss measurements which have been used to validate the transport model in section 3 [6]. Figure 2 presents the charged-coupled device (CCD)scintillator image from pulse 97493 at a time between sawteeth when the kink mode is observed to be strong.…”

Section: Experimental Scenariomentioning

confidence: 98%

“…The low frequency modes were identified as ideal kink modes via ECE and SXR phase measurements discussed more in reference [6]. The dominant mode has toroidal mode number n = 1 at a frequency of about 11 kHz.…”

Section: Experimental Scenariomentioning

confidence: 99%

“…The two instabilities provide the means for both resonant and non-resonant transport for analysis. Discussed extensively in reference [6], the saturated kink modes give rise to measureable fast ion losses in JET's Faraday cup fast ion loss detector [21] and scintillator probe [22].…”

Section: Experimental Scenariomentioning

confidence: 99%

“…Internal kink modes and sawteeth have previously been reported to alter the fast ion distribution and produce measureable losses [2][3][4][5][6]. The mechanisms of transport differ between resonant [7][8][9] and non-resonant [10,11] processes for the two instabilities.…”

Section: Introductionmentioning

confidence: 99%

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Numerical studies on saturated kink and sawtooth induced fast ion transport in JET ITER-like plasmas

Bonofiglo¹,

Podestà²,

Vallar³

et al. 2022

Nucl. Fusion

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This presentation examines the energetic particle transport induced by saturated kink modes and sawtooth crashes in JET deuterium plasmas. It is known that kink mode-resonant transport and phase-space redistribution from sawtooth crashes can drive strong fast ion transport with dependencies on particle pitch and energy. Measurements with JET's Faraday cup fast ion loss detector array have shown that the internal kink growth phase preceding sawtooth crashes produces substantial fast ion losses. This report will numerically investigate the dominant energetic particle transport mechanism with a detailed examination of the fast ion phase-space dependencies, resonances, orbit topology changes, induced losses, and redistribution associated with the long-lived, resonant, kink mode and non-resonant sawtooth crash. The ORBIT-kick model forms the basis of the transport studies with realistic fast ion distributions produced from TRANSP. A recently created reduced model for sawtooth induced transport is used while the saturated kink modes are modeled with ideal MHD codes. The simulations were further validated against experiment with a newly developed synthetic Faraday cup fast ion loss detector in addition to scintillator probe and neutron measurements.

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Section: Experimental Scenariomentioning

confidence: 87%

Section: Experimental Scenariomentioning

confidence: 98%

Section: Experimental Scenariomentioning

confidence: 99%

Section: Experimental Scenariomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical studies on saturated kink and sawtooth induced fast ion transport in JET ITER-like plasmas

Bonofiglo¹,

Podestà²,

Vallar³

et al. 2022

Nucl. Fusion

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Lost alpha Faraday cup foil noise characterization during Joint European Torus plasma post-processing analysis

Bonofiglo

Kiptily

Goloborod’ko

et al. 2022

Review of Scientific Instruments

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Capacitive plasma pickup is a well-known and difficult problem for plasma-facing edge diagnostics. This problem must be addressed to ensure an accurate and robust interpretation of the real signal measurements vs noise. The Faraday cup fast ion loss detector array of the Joint European Torus (JET) is particularly prone to this issue and can be used as a testbed to prototype solutions. The issue of separation and distinction between warranted fast ion signal and electromagnetic plasma noise has traditionally been solved with hardware modifications, but a more versatile post-processing approach is of great interest. This work presents post-processing techniques to characterize the signal noise. While hardware changes and advancements may be limited, the combination with post-processing procedures allows for more rapid and robust analysis of measurements. The characterization of plasma pickup noise is examined for alpha losses in a discharge from JET’s tritium campaign. In addition to highlighting the post-processing methodology, the spatial sensitivity of the detector array is also examined, which presents significant advantages for the physical interpretation of fast ion losses.

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Loss of energetic ions due to n = 1 internal kink instability in HL-2M

et al. 2023

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Effects of three-dimensional (3D) perturbations due to an unstable n = 1 (n is the toroidal mode number) internal kink (IK) on the energetic particles (EPs) are systematically investigated for the HL-2M tokamak, utilizing the MARS-F/K code [Liu et al., Phys. Plasmas 7, 3681–3690 (2000)] and a recently developed test particle tracing module. A high-beta sawteething HL-2M scenario, simulated by the TRANSP code [Breslau et al., Transp Computer Software (2018)], is chosen for this study. In general, the 3D perturbation associated with an unstable IK is found to affect the EP drift orbit, confinement, and loss in HL-2M. The instability-induced EP loss fraction is found to be typically less than 10%, without counting for the prompt orbit loss associated with the 2D equilibrium field for counter-current particles. The latter reaches about 16% in HL-2M. For co-current EPs, a 100 G 3D magnetic field (inside the plasma) due to the IK does not induce any EP loss assuming a static perturbation. A sawtooth-like time-varying perturbation field, with the peak amplitude reaching 1000 G, can however produce about 30% loss for the co-current EPs in HL-2M. The majority of lost EPs tend to strike the lower divertor region, with a small fraction of particles striking the low-field side mid-plane region of the limiting surface.

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Simulating energetic particle losses in JET plasmas with a reverse integration biasing scheme

Cited by 5 publications

References 51 publications

Numerical studies on saturated kink and sawtooth induced fast ion transport in JET ITER-like plasmas

Numerical studies on saturated kink and sawtooth induced fast ion transport in JET ITER-like plasmas

Lost alpha Faraday cup foil noise characterization during Joint European Torus plasma post-processing analysis

Loss of energetic ions due to n = 1 internal kink instability in HL-2M

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