Dependence of fast-ion transport on the nature of the turbulence in the Large Plasma Device

Zhou, Shu; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Carter, T. A.; Vincena, S.; Tripathi, S. K. P.
August 2011
Physics of Plasmas;Aug2011, Vol. 18 Issue 8, p082104
Academic Journal
Strong turbulent waves (δn/n ∼0.5, f ∼5-40 kHz) are observed in the upgraded Large Plasma Device [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)] on density gradients produced by an annular obstacle. Energetic lithium ions (Efast/Ti≥300, ρfast/ρs~10) orbit through the turbulent region. Scans with a collimated analyzer and with probes give detailed profiles of the fast ion spatial distribution and of the fluctuating wave fields. The characteristics of the fluctuations are modified by changing the plasma species from helium to neon and by modifying the bias on the obstacle. Different spatial structure sizes (Ls) and correlation lengths (Lcorr) of the wave potential fields alter the fast ion transport. The effects of electrostatic fluctuations are reduced due to gyro-averaging, which explains the difference in the fast-ion transport. A transition from super-diffusive to sub-diffusive transport is observed when the fast ion interacts with the waves for most of a wave period, which agrees with theoretical predictions.


Related Articles

  • Imaging of turbulent structures and tomographic reconstruction of TORPEX plasma emissivity. Iraji, D.; Furno, I.; Fasoli, A.; Theiler, C. // Physics of Plasmas;Dec2010, Vol. 17 Issue 12, p122304 

    In the TORPEX [A. Fasoli et al., Phys. Plasmas 13, 055902 (2006)], a simple magnetized plasma device, low frequency electrostatic fluctuations associated with interchange waves, are routinely measured by means of extensive sets of Langmuir probes. To complement the electrostatic probe...

  • Compact wide-aperture hyperbolic analyzers. Curtis, C. C.; Hsieh, K. C. // Review of Scientific Instruments;Nov88, Vol. 59 Issue 11, p2424 

    Compact electrostatic analyzers that employ a new geometry are described. They accept collimated beams of ions through relatively wide (non-slit-like) inlet apertures and focus them at various locations, depending on the ion energy per charge, along rectangular position-sensing detectors. Each...

  • Nonlinear fluid closure: Three-mode slab ion temperature gradient problem with diffusion. Holod, I.; Weiland, J.; Zagorodny, A. // Physics of Plasmas;Apr2002, Vol. 9 Issue 4, p1217 

    The three-mode slab ion temperature gradient problem was considered. Starting from the drift kinetic equation with nonlinear term and diffusion, the hierarchy of fluid equations up to fourth moment was developed. As a closure, the nonlinear fluid closure by N. Mattor and S. Parker [Phys. Rev....

  • Bicoherence in electrostatic turbulence driven by high magnetohydrodynamic activity in Tokamak Chauffage Alfvén Brésilien. dos Santos Lima, G. Z.; Guimarães-Filho, Z. O.; Batista, A. M.; Caldas, I. L.; Lopes, S. R.; Viana, R. L.; Nascimento, I. C.; Kuznetsov, Yu. K. // Physics of Plasmas;Apr2009, Vol. 16 Issue 4, p042508 

    During some discharges in Tokamak Chauffage Alfvén Brésilien [R. M. O. Galvão et al., Plasma Phys. Controlled Fusion 43, 1181 (2001)] high magnetohydrodynamic activity may appear with a peaked frequency spectrum. Whenever this peak occurs, the ambient broadband electrostatic turbulence...

  • Turbulence and transport suppression scaling with flow shear on the Large Plasma Device. Schaffner, D. A.; Carter, T. A.; Rossi, G. D.; Guice, D. S.; Maggs, J. E.; Vincena, S.; Friedman, B. // Physics of Plasmas;May2013, Vol. 20 Issue 5, p055907 

    Continuous control over azimuthal flow and shear in the edge of the Large Plasma Device (LAPD) [W. Gekelman et al., Rev. Sci. Instr. 62, 2875 (1991)] has been achieved using a biasable limiter. This flow control has allowed a careful study of the effect of flow shear on pressure-gradient-driven...

  • Edge transport and turbulence reduction with lithium coated plasma facing components in the National Spherical Torus Experiment. Canik, J. M.; Maingi, R.; Kubota, S.; Ren, Y.; Bell, R. E.; Callen, J. D.; Guttenfelder, W.; Kugel, H. W.; LeBlanc, B. P.; Osborne, T. H.; Soukhanovskii, V. A. // Physics of Plasmas;May2011, Vol. 18 Issue 5, p056118 

    The coating of plasma facing components (PFCs) with lithium improves energy confinement and eliminates ELMs in the National Spherical Torus Experiment, the latter due to a relaxation of the density and pressure profiles that reduces the drive for peeling-ballooning modes. 2-D interpretive...

  • Sheared-flow induced confinement transition in a linear magnetized plasma. Zhou, S.; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Carter, T. A.; Vincena, S.; Friedman, B.; Schaffner, D. // Physics of Plasmas;Jan2012, Vol. 19 Issue 1, p012116 

    A magnetized plasma cylinder (12 cm in diameter) is induced by an annular shape obstacle at the Large Plasma Device [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)]. Sheared azimuthal flow is driven at the edge of the plasma cylinder...

  • Nonlinear instability in simulations of Large Plasma Device turbulence. Friedman, B.; Carter, T. A.; Umansky, M. V.; Schaffner, D.; Joseph, I. // Physics of Plasmas;May2013, Vol. 20 Issue 5, p055704 

    Several simulations of turbulence in the Large Plasma Device (LAPD) [Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)] are energetically analyzed and compared with each other and with the experiment. The simulations use the same model, but different axial boundary conditions. They employ...

  • Crystal Collimation at RHIC. Fuller III, R. P.; Drees, A.; Gassner, D.; Hammons, L.; McIntyre, G.; Peggs, S.; Trbojevic, D.; Biryukov, V.; Chesnokov, Y.; Terekhov, V. // AIP Conference Proceedings;2003, Vol. 693 Issue 1, p192 

    Crystal Channeling occurs when an ion enters a crystal with a small angle with respect to the crystal planes, The electrostatic interaction between the incoming ion and the lattice causes the ion to follow the crystal planes. By mechanically bending a crystal, it is possible to use a crystal to...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics