ASCOT simulations of 14 MeV neutron rates in W7-X: effect of magnetic configuration

Kontula, J.; Koschinsky, J. P.; Äkäslompolo, S.; Kurki-Suonio, T.; Team, W X

doi:10.1088/1361-6587/abd981

Cited by 11 publications

(9 citation statements)

References 30 publications

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“…The nature of Alfvénic activity and role of magnetic islands on fast ion confinement will be explored through carefully designed experiments. Finally, once W7-X begins operation with deuterium, neutron diagnostics will become available for triton burn-up studies [25].…”

Section: Discussionmentioning

confidence: 99%

First neutral beam experiments on Wendelstein 7-X

Team¹,

Lazerson²,

Ford³

et al. 2021

Nucl. Fusion

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In the previous divertor campaign, the Wendelstein 7-X (W7-X) device injected 3.6 MW of neutral beam heating power allowing for the achievement of densities approaching 2 × 10 20 m −3 , and providing the first initial assessment of fast ion confinement in a drift optimized stellarator. The neutral beam injection (NBI) system on W7-X is comprised of two beam boxes with space for four radio frequency sources each. The 3.6 MW of heating reported in this work was achieved with two sources in the NI21 beam box. The effect of combined electron-cyclotron resonance heating (ECRH) and NBI was explored through a series of discharges varying both NBI and ECRH power. Discharges without ECRH saw a linear increase in the line-integrated plasma density, and strong peaking of the core density, over the

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Section: Discussionmentioning

confidence: 99%

First neutral beam experiments on Wendelstein 7-X

Team¹,

Lazerson²,

Ford³

et al. 2021

Nucl. Fusion

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“…The potential changes due to the EIC can be the reason for inducing significant transport. The detailed analysis of our understanding of the transport process of tritons due to EIC using numerical simulations such as GNET [56]/DELTA5D [57] plus MCNP6 models [58] or ASCOT [59] plus Serpent [60] models and comparison of the transport process of P-NB ions will form the basis for future work.…”

Section: Mev Triton Transport Due To Eicmentioning

confidence: 99%

A study of beam ion and deuterium–deuterium fusion-born triton transports due to energetic particle-driven magnetohydrodynamic instability in the large helical device deuterium plasmas

et al. 2021

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Understanding energetic particle transport due to magnetohydrodynamic instabilities excited by energetic particles is essential to apprehend alpha particle confinement in a fusion burning plasma. In the large helical device (LHD), beam ion and deuterium–deuterium fusion-born triton transport due to resistive interchange mode destabilized by helically-trapped energetic ions (EIC) are studied employing comprehensive neutron diagnostics, such as the neutron flux monitor and a newly developed scintillating fiber detector characterized by high detection efficiency. Beam ion transport due to EIC is studied in deuterium plasmas with full deuterium or hydrogen/deuterium beam injections. The total neutron emission rate (S n) measurement indicates that EIC induces about a 6% loss of passing transit beam ions and a 60% loss of helically-trapped ions. The loss rate of helically-trapped ions, which drive EIC, is larger than the loss rate of passing transit beam ions. Furthermore, the drop of S n increasing linearly with the EIC amplitude shows that barely confined beam ions existing near the confinement-loss boundary are lost due to EIC. In full deuterium conditions, a study of deuterium–deuterium fusion-born triton transport due to EIC is performed by time-resolved measurement of total secondary deuterium–tritium neutron emission rate (S n_DT). Drop of S n_DT increases substantially with EIC amplitude to the third power and reaches up to 30%. The relation shows that not only tritons confined in confined-loss boundary, but also tritons confined in the inner region of a plasma, are substantially transported.

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“…To date most analysis of the W7-X NBI heating has been done with a gyro center model. Gyro orbit (or full-orbit) simulations have only been invoked in the edge for particle loss studies [7][8][9] and in the core for Triton burn-up studies [10]. In this work a W7-X equilibria with fixed kinetic profiles and varying magnetic field strength (from 0.75 to 2.5 T) are assessed both with gyro center and gyro orbit models.…”

Section: Introductionmentioning

confidence: 99%

Gyro orbit simulations of neutral beam injection in Wendelstein 7-X

et al. 2023

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Simulations exploring neutral beam operation in Wendelstein 7-X (W7- X) at reduced magnetic field are performed using a newly implemented gyro orbit model in the BEAMS3D code. Operation at field strengths below the nominal 2.5 T are seen as a path to explore both high beta plasmas and as a means to access magnetic configurations not possible at 2.5T. As the field strength becomes smaller, the gyro radius for 55 keV fast protons grows from ∼1 cm at 2.5 T to ∼5 cm at 0.75 T in a device with minor radius ∼50 cm bringing into question the applicability of the gyro center approximation. To address this a gyro orbit model was implemented in the BEAMS3D code. Agreement is found between the gyro center and gyro orbit models in a circular cross section tokamak equilibrium at high field. A set of W7-X equilibria are assessed with fixed density and temperature profiles but decreasing magnetic field strength (increasing plasma beta). Neutral beam deposition is found to be mostly unaffected with changes in the core of the plasma associated with the Shafranov-shift. In general good agreement is found between gyro orbit and gyro center simulations at 2.5 T. Both models indicate increasing losses with decreasing magnetic field strength with the gyro orbit losses being higher at all field strengths. Gyro orbit simulations to the first wall of W7-X show a change in loss pattern with decreasing magnetic field strength. A preliminary assessment of losses to fast ion loss detectors are made.

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ASCOT simulations of 14 MeV neutron rates in W7-X: effect of magnetic configuration

Cited by 11 publications

References 30 publications

First neutral beam experiments on Wendelstein 7-X

First neutral beam experiments on Wendelstein 7-X

A study of beam ion and deuterium–deuterium fusion-born triton transports due to energetic particle-driven magnetohydrodynamic instability in the large helical device deuterium plasmas

Gyro orbit simulations of neutral beam injection in Wendelstein 7-X

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