POP Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

Search Issue | RSS Feeds RSS
Previous Issue Next Issue

Aug 2009

Volume 16, Issue 8, Articles (08xxxx)

Issue Cover Spotlight Figure

Phys. Plasmas 16, 082701 (2009); http://dx.doi.org/10.1063/1.3195065 (14 pages)

I. V. Igumenshchev, F. J. Marshall, J. A. Marozas, V. A. Smalyuk, R. Epstein, V. N. Goncharov, T. J. B. Collins, T. C. Sangster, and S. Skupsky
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds
back to top Nonlinear Phenomena, Turbulence, Transport

Hamiltonian derivation of the Charney–Hasegawa–Mima equation

E. Tassi, C. Chandre, and P. J. Morrison

Phys. Plasmas 16, 082301 (2009); http://dx.doi.org/10.1063/1.3194275 (5 pages) | Cited 6 times

Online Publication Date: 3 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The Charney–Hasegawa–Mima equation is an infinite-dimensional Hamiltonian system with dynamics generated by a noncanonical Poisson bracket. Here a first principle Hamiltonian derivation of this system, beginning with the ion fluid dynamics and its known Hamiltonian form, is given.
Show PACS
52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)
52.35.Kt Drift waves

Theory of fine-scale zonal flow generation from trapped electron mode turbulence

Lu Wang and T. S. Hahm

Phys. Plasmas 16, 082302 (2009); http://dx.doi.org/10.1063/1.3195069 (7 pages) | Cited 3 times

Online Publication Date: 5 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Most existing zonal flow generation theory has been developed with a usual assumption of qrρθi⪡1 (qr is the radial wave number of zonal flow and ρθi is the ion poloidal gyroradius). However, recent nonlinear gyrokinetic simulations of trapped electron mode turbulence exhibit a relatively short radial scale of the zonal flows with qrρθi ∼ 1 [Z. Lin et al., Proceedings of the 21st International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Chengdu, China, 2006 (International Atomic Energy Agency, Vienna, 2006); D. Ernst et al., Phys. Plasmas 16, 055906 (2009)] . This work reports an extension of zonal flow growth calculation to this short wavelength regime via the wave kinetics approach. A generalized expression for the polarization shielding for arbitrary radial wavelength [L. Wang and T. S. Hahm, Phys. Plasmas 16, 062309 (2009)] which extends the Rosenbluth–Hinton formula in the long wavelength limit is applied.
Show PACS
52.25.Dg Plasma kinetic equations
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)
52.65.Kj Magnetohydrodynamic and fluid equation
52.35.Ra Plasma turbulence

A geometry interface for gyrokinetic microturbulence investigations in toroidal configurations

P. Xanthopoulos, W. A. Cooper, F. Jenko, Yu. Turkin, A. Runov, and J. Geiger

Phys. Plasmas 16, 082303 (2009); http://dx.doi.org/10.1063/1.3187907 (13 pages) | Cited 8 times

Online Publication Date: 6 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The GENE/GIST code package is developed for the investigation of plasma microturbulence, suitable for both stellarator and tokamak configurations. The geometry module is able to process typical equilibrium files and create the interface for the gyrokinetic solver. The analytical description of the method for constructing the geometric elements is documented, together with several numerical evaluation tests. As a concrete application of this product, a cross-machine comparison of the anomalous ion heat diffusivity is presented.
Show PACS
52.65.Tt Gyrofluid and gyrokinetic simulations
52.35.Ra Plasma turbulence
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)
52.25.Fi Transport properties
52.55.Jd Magnetic mirrors, gas dynamic traps
52.55.Fa Tokamaks, spherical tokamaks

Effect of self-focusing on third harmonic generation by a Gaussian beam in a collisional plasma

Mahendra Singh Sodha, Mohammad Faisal, and M. P. Verma

Phys. Plasmas 16, 082304 (2009); http://dx.doi.org/10.1063/1.3194274 (7 pages) | Cited 6 times

Online Publication Date: 11 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this paper the third harmonic generation caused by the self-focusing of a Gaussian electromagnetic beam in collisional plasmas has been investigated. The wave equations for the fundamental and the third harmonic fields have been solved in the paraxial approximation. The wave frequency has been assumed to be much larger than the electron collision frequency. The generation of the third harmonic considering self-focusing has been investigated and graphically presented. It is seen that the self-focusing of the fundamental beam enhances the power of the third harmonic output indicating that the region of third harmonic generation is localized near the axis of the beam. The dependence of the third harmonic power on the distance of propagation for different values of initial fundamental power, beam width, and plasma density has also been plotted and discussed.
Show PACS
52.40.Mj Particle beam interactions in plasmas
52.25.-b Plasma properties
52.40.Db Electromagnetic (nonlaser) radiation interactions with plasma

Magnetohydrodynamic dissipation range spectra for isotropic viscosity and resistivity

P. W. Terry and V. Tangri

Phys. Plasmas 16, 082305 (2009); http://dx.doi.org/10.1063/1.3200901 (10 pages) | Cited 2 times

Online Publication Date: 11 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Dissipation range spectra for incompressible magnetohydrodynamic turbulence are derived for isotropic viscosity μ and resistivity η. The spectra are obtained from heuristic closures of spectral transfer correlations for cases with Pm = μ/η ≤ 1, where Pm is the magnetic Prandtl number. Familiar inertial range power laws are modified by exponential factors that dominate spectral falloff in the dissipation range. Spectral forms are sensitive to alignment between flow and magnetic field. There are as many as four Kolmogorov wavenumbers that parametrize the transition between inertial and dissipative behavior and enter corresponding spectral forms. They depend on the values of the viscosity and resistivity and on the nature of alignment in inertial and dissipation ranges.
Show PACS
52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)
52.35.Vd Magnetic reconnection
52.65.Kj Magnetohydrodynamic and fluid equation
52.25.Fi Transport properties
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.35.Ra Plasma turbulence

Wavelet-based coherent vorticity sheet and current sheet extraction from three-dimensional homogeneous magnetohydrodynamic turbulence

Katsunori Yoshimatsu, Yuji Kondo, Kai Schneider, Naoya Okamoto, Hiroyuki Hagiwara, and Marie Farge

Phys. Plasmas 16, 082306 (2009); http://dx.doi.org/10.1063/1.3195066 (11 pages) | Cited 8 times

Online Publication Date: 14 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A method for extracting coherent vorticity sheets and current sheets out of three-dimensional homogeneous magnetohydrodynamic (MHD) turbulence is proposed, which is based on the orthogonal wavelet decomposition of the vorticity and current density fields. Thresholding the wavelet coefficients allows both fields to be split into coherent and incoherent parts. The fields to be analyzed are obtained by direct numerical simulation (DNS) of forced incompressible MHD turbulence without mean magnetic field, using a classical Fourier spectral method at a resolution of 5123. Coherent vorticity sheets and current sheets are extracted from the DNS data at a given time instant. It is found that the coherent vorticity and current density preserve both the vorticity sheets and the current sheets present in the total fields while retaining only a few percent of the degrees of freedom. The incoherent vorticity and current density are shown to be structureless and of mainly dissipative nature. The spectral distributions of kinetic and magnetic energies of the coherent fields only differ in the dissipative range, while the corresponding incoherent fields exhibit near-equipartition of energy. The probability distribution functions of total and coherent fields for both vorticity and current density coincide almost perfectly, while the incoherent fields have strongly reduced variances. Studying the energy flux confirms that the nonlinear dynamics is fully captured by the coherent fields only.
Show PACS
47.65.-d Magnetohydrodynamics and electrohydrodynamics
47.32.-y Vortex dynamics; rotating fluids
47.27.-i Turbulent flows
02.60.-x Numerical approximation and analysis
02.30.Nw Fourier analysis

On shear viscosity and the Reynolds number of magnetohydrodynamic turbulence in collisionless magnetized plasmas: Coulomb collisions, Landau damping, and Bohm diffusion

Joseph E. Borovsky and S. Peter Gary

Phys. Plasmas 16, 082307 (2009); http://dx.doi.org/10.1063/1.3155134 (22 pages) | Cited 5 times

Online Publication Date: 18 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
For a collisionless plasma, the magnetic field math enables fluidlike behavior in the directions perpendicular to B; however, fluid behavior along math may fail. The magnetic field also introduces an Alfven-wave nature to flows perpendicular to math. All Alfven waves are subject to Landau damping, which introduces a flow dissipation (viscosity) in collisionless plasmas. For three magnetized plasmas (the solar wind, the Earth’s magnetosheath, and the Earth’s plasma sheet), shear viscosity by Landau damping, Bohm diffusion, and by Coulomb collisions are investigated. For magnetohydrodynamic turbulence in those three plasmas, integral-scale Reynolds numbers are estimated, Kolmogorov dissipation scales are calculated, and Reynolds-number scaling is discussed. Strongly anisotropic Kolmogorov k−5/3 and mildly anisotropic Kraichnan k−3/2 turbulences are both considered and the effect of the degree of wavevector anisotropy on quantities such as Reynolds numbers and spectral-transfer rates are calculated. For all three plasmas, Braginskii shear viscosity is much weaker than shear viscosity due to Landau damping, which is somewhat weaker than Bohm diffusion.
Show PACS
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)
52.35.Ra Plasma turbulence
96.20.Br Origin and evolution
52.40.Kh Plasma sheaths
94.30.-d Physics of the magnetosphere

Clustering of passive impurities in magnetohydrodynamic turbulence

H. Homann, J. Bec, H. Fichtner, and R. Grauer

Phys. Plasmas 16, 082308 (2009); http://dx.doi.org/10.1063/1.3204100 (9 pages) | Cited 2 times

Online Publication Date: 31 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The transport of heavy, neutral, or charged pointlike particles by three-dimensional incompressible, resistive magnetohydrodynamic turbulence is investigated by means of high-resolution numerical simulations. The spatial distribution of such impurities is observed to display strong deviations from homogeneity, both at dissipative and inertial range scales. Neutral particles tend to cluster in the vicinity of coherent vortex sheets due to their viscous drag with the flow, leading to the simultaneous presence of very concentrated and almost empty regions. The signature of clustering is different for charged particles because they are influenced both by the drag and the Lorentz forces. The regions of spatial inhomogeneities change due to attractive and repulsive vortex sheets. While small charges increase clustering, larger charges have a reverse effect.
Show PACS
52.30.-q Plasma dynamics and flow
52.65.-y Plasma simulation
52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close