| 1. |
- Pusztai, Istvan, 1983, et al.
(författare)
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Can we study the transport of MeV ions without generating fusion alphas?
- 2015
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Ingår i: 57th Annual Meeting of the APS Division of Plasma Physics. ; 60:19, s. PP12.00093-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The novel ion cyclotron resonance heating method, utilizing three ion species, allows the generation of energetic trace minorities in the MeV range [Ye. O. Kazakov et al., 2015, Nucl. Fusion 55, 032001]. We survey which aspects of alpha particle transport may be accessed experimentally without D-T operation, such as during the non-activated phase of ITER, through a numerical investigation of the transport properties of RF heated 3He resonant ions in a 4He−H mixture plasma. The turbulent transport is simulated using the recently developed version of the gyrokinetic code GS2 that can handle strongly non-Maxwellian species [G. J. Wilkie et al., 2015, J. Plasma Phys. 81, 905810306], while the collisional transport is studied taking the temperature anisotropy of the 3He species into account.
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| 2. |
- Wilkie, George, 1983, et al.
(författare)
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Validating modeling assumptions of alpha particles in electrostatic turbulence
- 2015
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Ingår i: Journal of Plasma Physics. - 0022-3778 .- 1469-7807. ; 81:3
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Tidskriftsartikel (refereegranskat)abstract
- To rigorously model fast ions in fusion plasmas, a non-Maxwellian equilibrium distribution must be used. In this work, the response of high-energy alpha particles to electrostatic turbulence has been analyzed for several different tokamak parameters. Our results are consistent with known scalings and experimental evidence that alpha particles are generally well confined: on the order of several seconds. It is also confirmed that the effect of alphas on the turbulence is negligible at realistically low concentrations, consistent with linear theory. It is demonstrated that the usual practice of using a high-temperature Maxwellian, while previously shown to give an adequate order-of-magnitude estimate of the diffusion coefficient, gives incorrect estimates for the radial alpha particle flux, and a method of correcting it in general is provided. Furthermore, we see that the timescales associated with collisions and transport compete at moderate energies, calling into question the assumption that alpha particles remain confined to a flux surface that is used in the derivation of the slowing-down distribution.
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