A synthetic diagnostic for validation of electron gyroradius scale turbulence simulations against coherent scattering measurements

Poli, F. M.; Ethier, S.; Wang, W.; Hahm, T. S.; Mazzucato, E.; Smith, D. R.
November 2010
Physics of Plasmas;Nov2010, Vol. 17 Issue 11, p112514
Academic Journal
Comparison between spectra of short-scale density fluctuations measured with coherent electromagnetic scattering experiments and those extracted from space-resolved numerical simulations is affected by a number of systematic errors. These include the locality of scattering measurements, the different domain covered (space-resolved simulations versus wavenumber resolved measurements), and the stationarity of simulated nonlinear spectra. To bridge the gap between theory-simulations and experiments, a synthetic diagnostic for high-k scattering measurements has been developed. This synthetic scattering predicts the propagation of the beam in an anisotropic, inhomogeneous plasma and accounts for the spatial variation of the instrumental transfer function. The latter, in particular, is proven to provide an important calibration factor not only for the simulated spectra, but also for the measured ones, allowing the use of the synthetic diagnostic in predictive mode. Results from a case study for National Spherical Torus Experiment plasmas using high-k tangential scattering system [Smith et al., Rev. Sci. Instrum. 75, 3840 (2004)] and the gyrokinetic tokamak simulation code [Wang et al., Phys. Plasmas 13, 092505 (2006)] are presented.


Related Articles

  • Wall-modeling in large eddy simulation: Length scales, grid resolution, and accuracy. Kawai, Soshi; Larsson, Johan // Physics of Fluids;Jan2012, Vol. 24 Issue 1, p015105 

    This paper addresses one of the most persistent errors in wall-modeled large eddy simulation: the inevitable presence of numerical and subgrid modeling errors in the first few grid points off the wall, which leads to the so-called 'log-layer mismatch' with its associated 10-15% error in the...

  • Research on Multipath-Caused MLS Angle-Measurement Error Using Main Lobe Gaussian Replacement Technology. Huaxin Wu; Xiubin Zhao; Chuanjin Dai // Journal of Computers;Jul2011, Vol. 6 Issue 7, p1353 

    Electromagnetic scattering caused by the site environment of airports will cause multipath effect. In the presence of multipath, the measured angle position, which is derived through the measuring of the time interval between "From" and "To" scanning pulse pairs, will deviate from the actual...

  • Efficiency enhancement in seeded and self-amplified spontaneous emission free-electron lasers by means of a tapered wiggler. Freund, H. P.; Miner, W. H. // Journal of Applied Physics;Jun2009, Vol. 105 Issue 11, p113106 

    The enhancement of the efficiency in free-electron lasers (FELs) through the use of a tapered wiggler is well known. The physics of the tapered wiggler interaction has been studied in theory and simulation, and large efficiency enhancements have been observed in the laboratory in oscillators and...

  • Operational Trans-Resistance Amplifier Based Tunable Wave Active Filter. BOTHRA, Mayank; PANDEY, Rajeshwari; PANDEY, Neeta; PAUL, Sajal K. // Radioengineering;Apr2013, Vol. 22 Issue 1, p159 

    In this paper, Operational Trans-Resistance Amplifier (OTRA) based wave active filter structures are presented. They are flexible and modular, making them suitable to implement higher order filters. The passive resistors in the proposed circuit can be implemented using matched transistors,...

  • Anisotropic electron temperature measurements without knowing the spectral transmissivity for a JT-60SA Thomson scattering diagnostic. Tojo, H.; Hatae, T.; Yatsuka, E.; Itami, K. // Review of Scientific Instruments;Oct2012, Vol. 83 Issue 10, p10E346 

    This paper focuses on a method for measuring the electron temperature (Te) without knowing the transmissivity using Thomson scattering diagnostic with a double-pass scattering system. Application of this method for measuring the anisotropic Te, i.e., the Te in the directions parallel (Te||) and...

  • Numerical modeling of coherent structures attendant on impurity propagation in the atmospheric boundary layer over a forest canopy. Gavrilov, K.; Morvan, D.; Accary, G.; Lyubimov, D.; Meradji, S.; Bessonov, O. // Fluid Dynamics;Feb2011, Vol. 46 Issue 1, p138 

    Three-dimensional large eddy simulation is used to solve the problem for a homogeneous forest canopy. The development of the Kelvin-Helmholtz instability above the canopy leads to the formation of coherent structures in the atmosphere flow, which are reproduced in the calculations. The...

  • Generation of residual energy in the turbulent solar wind. Gogoberidze, G.; Chapman, S. C.; Hnat, B. // Physics of Plasmas;Oct2012, Vol. 19 Issue 10, p102310 

    In situ observations of the fluctuating solar wind flow show that the energy of magnetic field fluctuations always exceeds that of the kinetic energy, and therefore the difference between the kinetic and magnetic energies, known as the residual energy, is always negative. The same behaviour is...

  • Anisotropic dynamics and sub-grid energy transfer in wall-turbulence. Cimarelli, A.; De Angelis, E. // Physics of Fluids;Jan2012, Vol. 24 Issue 1, p015102 

    Purpose of the present work is the analysis of the generalized Kolmogorov equation applied to the direct numerical simulation data of a turbulent channel flow. The multi-dimensional description of the anisotropic behavior of turbulent energy production, transport, and dissipation is shown to be...

  • The effect of spectral anisotropy of fast magnetosonic turbulence on the plasma heating at the proton kinetic scales. Markovskii, S. A.; Vasquez, Bernard J. // Physics of Plasmas;Nov2010, Vol. 17 Issue 11, p112902 

    The energy transport associated with the fast magnetosonic turbulence in a low-beta plasma is one of the possible driving forces of the solar wind. Two different kinds of the turbulence spectra are discussed in this paper: a unidirectional spectrum of the fluctuations propagating away from the...


Read the Article


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

Try another library?
Sign out of this library

Other Topics