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Analytic slowing-down distributions as modified by turbulent transport

Part of: PLA 17th European Fusion Theory Conference

Published online by Cambridge University Press:  13 November 2018

G. J. Wilkie Open the ORCID record for G. J. Wilkie [Opens in a new window]
G. J. Wilkie*
Affiliation:
Department of Physics, Chalmers University of Technology, Gothenburg 41258, Sweden
*
†Email address for correspondence: [email protected]
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Abstract

The effect of electrostatic microturbulence on fast particles rapidly decreases at high energy, but can be significant at moderate energy. Previous studies found that, in addition to changes in the energetic particle density, this results in non-trivial changes to the equilibrium velocity distribution. These effects have implications for plasma heating and the stability of Alfvén eigenmodes, but make multiscale simulations much more difficult without further approximations. Here, several related analytic model distribution functions are derived from first principles. A single dimensionless parameter characterizes the relative strength of turbulence relative to collisions, and this parameter appears as an exponent in the model distribution functions. Even the most simple of these models reproduces key features of the numerical phase-space transport solution and provides a useful a priori heuristic for determining how strong the effect of turbulence is on the redistribution of energetic particles in toroidal plasmas.

Keywords

fusion plasmaplasma confinementplasma heating
Type
Research Article
Information
Journal of Plasma Physics , Volume 84 , Issue 6 , December 2018 , 745840601
Copyright
© Cambridge University Press 2018 

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References

Abel, I. G., Plunk, G. G., Wang, E., Barnes, M., Cowley, S. C., Dorland, W. & Schekochihin, A. A. 2013 Multiscale gyrokinetics for rotating tokamak plasmas: fluctuations, transport and energy flows. Rep. Prog. Phys. 76 (11), 116201.Google Scholar
Abel, I. G., Wilkie, G. J. & Schekochihin, A. A.2018 Multiscale gyrokinetics for rotating tokamak plasmas III: energetic particles (in preparation).Google Scholar
Anderson, D., Batistoni, P. & Anderson, M. L. 1991 Influence of radial diffusion on triton burnup. Nucl. Fusion 31 (11), 2147.Google Scholar
Antonsen, T. M. & Lane, B. 1980 Kinetic equations for low frequency instabilities in inhomogeneous plasmas. Phys. Fluids 23 (6), 1205.Google Scholar
Brysk, H. 1973 Fusion neutron energies and spectra. Plasma Phys. 15 (7), 611.Google Scholar
Catto, P. J. 1987 Evaluation of the slowing down tail enhanced, neoclassical alpha particle energy flux. Phys. Fluids 30 (9), 2740–2744.Google Scholar
Frieman, E. A. & Chen, L. 1982 Nonlinear gyrokinetic equations for low-frequency electromagnetic waves in general plasma equilibria. Phys. Fluids 25 (3), 502.Google Scholar
Gaffey, J. D. 1976 Energetic ion distribution resulting from neutral beam injection in tokamaks. J. Plasma Phys. 16, 149–169.Google Scholar
Hauff, T., Pueschel, M. J., Dannert, T. & Jenko, F. 2009 Electrostatic and magnetic transport of energetic ions in turbulent plasmas. Phys. Rev. Lett. 102 (7).Google Scholar
Helander, P. & Sigmar, D. 2002 Collisional Transport in Magnetized Plasmas. Cambridge University Press.Google Scholar
Kim, J. Y., Horton, W. & Dong, J. Q. 1993 Electromagnetic effect on the toroidal ion temperature gradient mode. Phys. Fluids B 5 (11), 4030.Google Scholar
Kurki-Suonio, T., Asunta, O., Hirvijoki, E., Koskela, T., Snicker, A., Hauff, T., Jenko, F., Poli, E. & Sipilä, S. 2011 Fast ion power loads on ITER first wall structures in the presence of NTMs and microturbulence. Nucl. Fusion 51 (8), 083041.Google Scholar
Pueschel, M. J., Jenko, F., Schneller, M., Hauff, T., Günter, S. & Tardini, G. 2012 Anomalous diffusion of energetic particles: connecting experiment and simulations. Nucl. Fusion 52 (10), 103018.Google Scholar
Pusztai, I., Wilkie, G. J., Kazakov, Y. O. & Fülöp, T. 2016 Turbulent transport of MeV range cyclotron heated minorities as compared to alpha particles. Plasma Phys. Control. Fusion 58 (10), 105001.Google Scholar
Roach, C. M., Walters, M., Budny, R. V., Imbeaux, F., Fredian, T. W., Greenwald, M., Stillerman, J. A., Alexander, D. A., Carlsson, J., Cary, J. R. et al. 2008 The 2008 public release of the international multi-tokamak confinement profile database. Nucl. Fusion 48 (12), 125001.Google Scholar
Sigmar, D., Gormley, R. & Kamelander, G. 1993 Effects of anomalous alpha particle diffusion on fusion power coupling into tokamak plasma. Nucl. Fusion 33 (5), 677.Google Scholar
Wilkie, G. J.2015 Microturbulent transport of non-Maxwellian alpha particles. PhD thesis, University of Maryland.Google Scholar
Wilkie, G. J., Abel, I. G., Highcock, E. G. & Dorland, W. 2015 Validating modeling assumptions of alpha particles in electrostatic turbulence. J. Plasma Phys. 81 (03), 905810306.Google Scholar
Wilkie, G. J., Abel, I. G., Landreman, M. & Dorland, W. 2016 Transport and deceleration of fusion products in microturbulence. Phys. Plasmas 23 (6), 060703.Google Scholar
Wilkie, G. J., Iantchenko, A., Abel, I. G., Highcock, E., Pusztai, I.& JET Contributors 2018 First principles of modelling the stabilization of microturbulence by fast ions. Nucl. Fusion 58 (8), 082024.Google Scholar
Wilkie, G. J., Pusztai, I., Abel, I., Dorland, W. & Fülöp, T. 2017 Global anomalous transport of ICRH- and NBI-heated fast ions. Plasma Phys. Control. Fusion 59 (4), 044007.Google Scholar
Zhang, W., Decyk, V., Holod, I., Xiao, Y., Lin, Z. & Chen, L. 2010 Scalings of energetic particle transport by ion temperature gradient microturbulence. Phys. Plasmas 17 (5), 055902.Google Scholar