TITLE

Fully electromagnetic gyrokinetic eigenmode analysis of high-beta shaped plasmas

AUTHOR(S)
Belli, E. A.; Candy, J.
PUB. DATE
November 2010
SOURCE
Physics of Plasmas;Nov2010, Vol. 17 Issue 11, p112314
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
A new, more efficient method to compute unstable linear gyrokinetic eigenvalues and eigenvectors has been developed for drift-wave analysis of plasmas with arbitrary flux-surface shape, including both transverse and compressional magnetic perturbations. In high-beta, strongly shaped plasmas like in the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)], numerous branches of closely spaced unstable eigenmodes exist. These modes are difficult and time-consuming to adequately resolve with the existing linear initial-value solvers, which are further limited to the most unstable eigenmode. The new method is based on an eigenvalue approach and is an extension of the GYRO code [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)], reusing the existing discretization schemes in both real and velocity-space. Unlike recent methods, which use an iterative solver to compute eigenvalues of the relatively large gyrokinetic response matrix, the present scheme computes the zeros of the much smaller Maxwell dispersion matrix using a direct method. In the present work, the new eigensolver is applied to gyrokinetic stability analysis of a high-beta, NSTX-like plasma. We illustrate the smooth transformation from ion-temperature-gradient (ITG)-like to kinetic-ballooning (KBM)-like modes, and the formation of hybrid ITG/KBM modes, and further demonstrate the existence of high-k Alfvénic drift-wave 'cascades' for which the most unstable mode is a higher excited state along the field line. A new compressional electron drift wave, which is driven by a combination of strong beta and pressure gradient, is also identified for the first time. Overall, we find that accurate calculation of stability boundaries and growth rates cannot, in general, ignore the compressional component δB∥ of the perturbation.
ACCESSION #
55509443

 

Related Articles

  • Anomalous resistivity due to nonlinear lower-hybrid drift waves. Silin, I.; Büchner, J.; Vaivads, A. // Physics of Plasmas;Jun2005, Vol. 12 Issue 6, p062902 

    The generation of anomalous collision rate and resistivity by lower-hybrid drift waves is investigated. A general expression involving particle density and current perturbations and electromagnetic field fluctuations is used to estimate the effective collision frequency. Results of Vlasov-code...

  • Derivation of nonlinear Schrödinger equation for electrostatic and electromagnetic waves in fully relativistic two-fluid plasmas by the reductive perturbation method. Lee, Nam C. // Physics of Plasmas;Aug2012, Vol. 19 Issue 8, p082303 

    The reductive perturbation method is used to derive a generic form of nonlinear Schrödinger equation (NLSE) that describes the nonlinear evolution of electrostatic (ES)/electromagnetic (EM) waves in fully relativistic two-fluid plasmas. The matrix eigenvector analysis shows that there are two...

  • Lower-hybrid quasimode decay in a plasma cylinder. Praburam, G. // Physics of Fluids B: Plasma Physics;Jul91, Vol. 3 Issue 7, p1576 

    In the presence of an azimuthally symmetric lower-hybrid pump wave, a low-frequency density perturbation of frequency ω≊ωci having finite azimuthal mode number, generates a nonlinear current driving a lower-hybrid sideband wave. The sideband couples with the pump to produce a...

  • Finite length diocotron modes. Hilsabeck, T. J.; O'Neil, T. M. // Physics of Plasmas;Feb2001, Vol. 8 Issue 2, p407 

    Diocotron modes are discussed for a finite length nonneutral plasma column under the assumption of bounce averaged ExB drift dynamics and small Debye length. In this regime, which is common to experiments, Debye shielding forces the mode potential to be constant along field lines within the...

  • Generation of electromagnetic structures via modulational instability of drift waves. Smolyakov, A. I.; Krasheninnikov, S. I. // Physics of Plasmas;Jul2008, Vol. 15 Issue 7, p072302 

    Generation mechanism for large scale electromagnetic structures (blobs) is considered by employing the technique of four-wave interactions (modulational instability). It is shown that primary electrostatic turbulence may generate elongated electromagnetic structures with poloidal modulations....

  • Proton radiography as an electromagnetic field and density perturbation diagnostic (invited). Mackinnon, A. J.; Patel, P. K.; Town, R. P.; Edwards, M. J.; Phillips, T.; Lerner, S. C.; Price, D. W.; Hicks, D.; Key, M. H.; Hatchett, S.; Wilks, S. C.; Borghesi, M.; Romagnani, L.; Kar, S.; Toncian, T.; Pretzler, G.; Willi, O.; Koenig, M.; Martinolli, E.; Lepape, S. // Review of Scientific Instruments;Oct2004 Part I & II, Vol. 75 Issue 10, p3531 

    Laser driven proton beams have been used to diagnose transient fields and density perturbations in laser produced plasmas. Grid deflectometry techniques have been applied to proton radiography to obtain precise measurements of proton beam angles caused by electromagnetic fields in laser produced...

  • Electron transport and permittivity in a plasma with an arbitrary ionic charge. Brantov, A.; Bychenkov, V. Yu.; Rozmus, W. // Journal of Experimental & Theoretical Physics;May2008, Vol. 106 Issue 5, p983 

    Based on the solution of a linearized kinetic equation for electrons with a Landau collision integral, we develop a theory of electron transport for small perturbations in a completely ionized plasma with an arbitrary ionic charge that is free from any constraints on the characteristic...

  • Fully electromagnetic nonlinear gyrokinetic equations for tokamak edge turbulence. Hahm, T. S.; Lu Wang; Madsen, J. // Physics of Plasmas;Feb2009, Vol. 16 Issue 2, pN.PAG 

    An energy conserving set of the fully electromagnetic nonlinear gyrokinetic Vlasov equation and Maxwell’s equations, which is applicable to both L-mode turbulence with large amplitude and H-mode turbulence in the presence of high E×B shear has been derived. The phase-space action...

  • Plasma transport by relaxation of localized perturbations. Hossain, Murshed; Hu, Pung Nien; Kress, Michael; Blank, Albert A.; Grad, Harold // Physics of Fluids (00319171);Aug88, Vol. 31 Issue 8, p2165 

    Localized perturbations in temperature and density are introduced on a background (approximate) steady-state plasma. A simulation of the evolving plasma was carried out on a transport time scale. In all these simulations, the mass diffusion rate ?[sub ?] is significantly less than that, ?[sub...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

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

Try another library?
Sign out of this library

Other Topics