Collective scattering of electromagnetic waves and cross-B plasma diffusion

Grésillon, D.; Cabrit, B.; Villain, J. P.; Hanuise, C.; Truc, A.; Laviron, C.; Hennequin, Pascale; Gervais, F.; Quéméneur, A.; Garbet, X.; Payan, J; Devynck, P.

doi:10.1088/0741-3335/34/13/030

Cited by 26 publications

(8 citation statements)

References 7 publications

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“…directions, respectively. 30 This is consistent with the sign change of E r . In W7-AS, E r is derived from active charge exchange recombination spectroscopy and passive visible spectroscopy.…”

supporting

confidence: 84%

CO 2 laser based two-volume collective scattering instrument for spatially localized turbulence measurements

Saffman¹,

Zoletnik²,

Basse

et al. 2001

Review of Scientific Instruments

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We describe and demonstrate a two-volume collective scattering system for localized measurements of plasma turbulence. The finite crossfield correlation length of plasma turbulence combined with spatial variations in the magnetic field direction are used to obtain spatially localized turbulence measurements at the Wendelstein 7-AS fusion experiment. By comparing with localized measurements obtained using the single wide beam technique [Truc et al., Rev. Sci. Instrum. 63, 3716 (1992)] we provide a proof-of-principle demonstration of the two-beam method. An optimized configuration with large toroidal separation of the measurement volumes is predicted to be capable of providing spatial resolution better than 5 cm.

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supporting

confidence: 84%

CO 2 laser based two-volume collective scattering instrument for spatially localized turbulence measurements

Saffman¹,

Zoletnik²,

Basse

et al. 2001

Review of Scientific Instruments

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“…10 The most appropriate means for remotely investigating electron fluctuations inside plasmas is collective light scattering. 11 It has been used in very different situations in tokamaks, 12,13 space, 14 and magnetized laboratory devices. 15 The scattered light signal is proportional to the spatial Fourier transform of the density ñ͑k ជ , t͒, at a wave vector k ជ that is defined by the scattering geometry.…”

Section: Dispersion Relations Of Electron Density Fluctuations In a Hmentioning

confidence: 99%

Dispersion relations of electron density fluctuations in a Hall thruster plasma, observed by collective light scattering

et al. 2009

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International audienceKinetic models and numerical simulations of E×B plasma discharges predict microfluctuations at the scales of the electron cyclotron drift radius and the ion plasma frequency. With the help of a specially designed collective scattering device, the first experimental observations of small-scale electron density fluctuations inside the plasma volume are obtained, and observed in the expected ranges of spatial and time scales. The anisotropy, dispersion relations, form factor, amplitude, and spatial distribution of these electron density fluctuations are described and compared to theoretical expectations

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“…In this paper, we investigate the radial correlation reflectometry in the framework of a twodimensional model to describe its main features in the non-linear regime. Taking into account that, according to linear theory [15], the scattering efficiency is maximal for fluctuations possessing a small radial component of wave vector, comparable to the density scale length and making use of the fact that long scales are dominant in the tokamak turbulence [16] one can conclude that transition to the non-linear regime occurs via small angle multi-scattering. From a mathematical point of view it is quite natural, given the above assumptions, to base a non-linear model describing fluctuation reflectometry upon the WKB approximation, which is not limited to low-level fluctuations.…”

Section: General Approachmentioning

confidence: 99%

Two-dimensional non-linear theory of radial correlation reflectometry

Gusakov

Popov

2004

Plasma Phys. Control. Fusion

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As a result of the two-dimensional consideration, a general analytic approach to the non-linear regime of fluctuation reflectometry allowing determination of its spectral and correlation characteristics in explicit form is developed. The expressions for average signal and cross-correlation function of radial correlation reflectometry valid for arbitrary plasma density profile, turbulence spatial distribution and wave number spectra are derived. The analytical predictions are compared to the results of one-and two-dimensional numerical modelling.

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Collective scattering of electromagnetic waves and cross-B plasma diffusion

Abstract: loulunctdu Vx, DP 132. F 83957, 1.a Gude Ccdex. Frmce. +t "Associstion rurdtom-CEA. CE CJduJChe. I. 131(IX SI l'3uI Id, Dunner. trlncc

Cited by 26 publications

References 7 publications

CO 2 laser based two-volume collective scattering instrument for spatially localized turbulence measurements

CO 2 laser based two-volume collective scattering instrument for spatially localized turbulence measurements

Dispersion relations of electron density fluctuations in a Hall thruster plasma, observed by collective light scattering

Two-dimensional non-linear theory of radial correlation reflectometry

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