Studies of turbulence and transport in Alcator C-Mod H-mode plasmas with phase contrast imaging and comparisons with GYRO

Lin, L.; Porkolab, M.; Edlund, E. M.; Rost, J. C.; Fiore, C. L.; Greenwald, M.; Lin, Y.; Mikkelsen, D. R.; Tsujii, N.; Wukitch, S. J.
January 2009
Physics of Plasmas;Jan2009, Vol. 16 Issue 1, pN.PAG
Academic Journal
Recent advances in gyrokinetic simulation of core turbulence and associated transport requires an intensified experimental effort to validate these codes using state of the art synthetic diagnostics to compare simulations with experimental data. A phase contrast imaging (PCI) diagnostic [M. Porkolab, J. C. Rost, N. Basse et al., IEEE Trans. Plasma Sci. 34, 229 (2006)] is used to study H-mode plasmas in Alcator C-Mod [M. Greenwald, D. Andelin, N. Basse et al., Nucl. Fusion 45, S109 (2005)]. The PCI system is capable of measuring density fluctuations with high temporal (2 kHz–5 MHz) and wavenumber (0.5–55 cm-1) resolution. Recent upgrades have enabled PCI to localize the short wavelength turbulence in the electron temperature gradient range and resolve the direction of propagation (i.e., electron versus ion diamagnetic direction) of the longer wavelength turbulence in the ion temperature gradient (ITG) and trapped electron mode range. The studies focus on plasmas before and during internal transport barrier formation in an enhanced Dα H-mode plasma assisted with ion cyclotron resonance frequency heating. Nonlinear GYRO simulations have also been performed [J. Candy and R. E. Waltz, Phys. Rev. Lett. 91, 045001 (2003)] and the predicted fluctuation is compared against experimental measurements through a synthetic PCI diagnostic method. The simulated fluctuations from GYRO agree with experimental measurements in the ITG regime. GYRO also shows good agreement in transport predictions with experimental measurements after reducing the ion temperature gradient (∼15%) and adding E×B shear suppression, all within the experimental uncertainty.


Related Articles

  • Gyrokinetic δf particle simulation of trapped electron mode driven turbulence. Jianying Lang; Yang Chen; Parker, Scott E. // Physics of Plasmas;Aug2007, Vol. 14 Issue 8, p082315 

    The linear instabilities and nonlinear transport driven by collisionless trapped electron modes (CTEM) are systematically investigated using three-dimensional gyrokinetic δf particle-in-cell simulations. Scalings with local plasma parameters are presented. Simulation results are compared with...

  • Nonlocal transport in hot plasma. Part II. Brantov, A.; Bychenkov, V. // Plasma Physics Reports;Jul2014, Vol. 40 Issue 7, p505 

    The second part of the review, the first part of which was published earlier in Plasma Phys. Rep. 39, 698 (2013), is presented. A wide range of electromagnetic phenomena in laser plasma under nonlocal transport conditions requiring kinetic consideration are described. Among them, there are...

  • Linear Stability Analysis of a Hot Plasma in a Solid Torus. Nguyen, Toan; Strauss, Walter // Archive for Rational Mechanics & Analysis;Feb2014, Vol. 211 Issue 2, p619 

    This paper is a first step toward understanding the effect of toroidal geometry on the rigorous stability theory of plasmas. We consider a collisionless plasma inside a torus, modeled by the relativistic Vlasov-Maxwell system. The surface of the torus is perfectly conducting and it reflects the...

  • The Vlasov-Poisson model and the validity of a numerical approach. Califano, F.; Galeotti, L.; Mangeney, A. // Physics of Plasmas;Aug2006, Vol. 13 Issue 8, p082102 

    Our aim in this work is to show that the final macroscopic state of a noncollisional plasma system, computed through numerical simulations, depends on artificial small scale effects induced by the used numerical scheme and/or grid discretization. By using the continuous, Hamiltonian...

  • Anomalous resistivity of current-driven isothermal plasmas due to phase space structuring. Büchner, Jörg; Elkina, Nina // Physics of Plasmas;Aug2006, Vol. 13 Issue 8, p082304 

    The anomalous electric resistivity of collisionless plasmas is an important issue in the physics of hot plasmas, e.g., in the context of auroral particle acceleration and of reconnection in the solar corona. The linear stability theory of isothermal current driven space plasmas predicts an...

  • Global gyrokinetic stability of collisionless microtearing modes in large aspect ratio tokamaks. Swamy, Aditya K.; Ganesh, R.; Chowdhury, J.; Brunner, S.; Vaclavik, J.; Villard, L. // Physics of Plasmas;2014, Vol. 21 Issue 8, p1 

    Linear full radius gyrokinetic calculations show the existence of unstable microtearing modes (MTMs) in purely collisionless, high temperature, large aspect ratio tokamak plasmas. The present study takes into account fully gyrokinetic highly passing ions and electrons. The global 2-D structures...

  • Two-dimensional plasma expansion in a magnetic nozzle: Separation due to electron inertia. Ahedo, Eduardo; Merino, Mario // Physics of Plasmas;Aug2012, Vol. 19 Issue 8, p083501 

    A previous axisymmetric model of the supersonic expansion of a collisionless, hot plasma in a divergent magnetic nozzle is extended here in order to include electron-inertia effects. Up to dominant order on all components of the electron velocity, electron momentum equations still reduce to...

  • Effects of edge plasma turbulence on radial correlation length measurements with BES. Gianakon, T. A.; Fonck, R. J.; Callen, J. D.; Durst, R. D.; Kim, J. S.; Paul, S. F. // Review of Scientific Instruments;Oct92, Vol. 63 Issue 10, p4931 

    The recently developed technique of beam emission spectroscopy (BES) provides a tool to study long-wavelength density turbulence (coherence length » ion gyroradius) in hot tokamak plasmas. To provide an accurate conversion of the measured light intensity fluctuations to a local ñ/n density...

  • Magnetic field generation in shock waves and jets. Martianov, V.; Derishev, E.; Kocharovsky, V.; Kocharovsky, Vl. // AIP Conference Proceedings;2005, Vol. 801 Issue 1, p357 

    The origin, formation, structure, and long-term evolution of the self-consistent magnetic field in collisionless relativistic plasma outflows of astrophysical interest are investigated. The main attention is paid to various models allowing approximate analytical investigation as well as 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