Polarization of radiation in incoherent Thomson scattering by high temperature plasma

Segrè, S. E.; Zanza, V.

doi:10.1063/1.874110

Cited by 20 publications

(67 citation statements)

References 6 publications

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“…The resulting analytical spectrum includes both thermal broadening effects, blueshift due to electron-headlighting, and a term commonly referred to as a "depolarization factor" which includes both relativistic headlighting effects and a reduction of scattered spectral intensity due to polarization effects. Rather than utilizing this approach, we follow the Stokes vector and Mueller matrix formalism of Ref [6].…”

Section: Theoretical Resultsmentioning

confidence: 99%

“…The work in Ref [6] contains an error in the power of the term (1 − β s ) originating in the Liénard-Wiechert expression for the scattered field. While there is contention in the literature over the power of this term for an infinite scattering volume, for a finite volume the appropriate term is unambiguously (1 − β s ) 5 rather than (1 − β s ) 6 . At fusion-grade temperatures this can introduce non-negligible error.…”

Section: Theoretical Resultsmentioning

confidence: 99%

“…In addition to thermal broadening of the scattered spectrum, relativistic effects at high temperature also lead to significant changes to the polarization state of scattered photons. The resulting depolarization of the scattered light can depend strongly on the electron temperature, leading other authors to propose Thomson polarization techniques as an alternative temperature measurement diagnostic [5,6]. The proposed techniques involve up to four measurements of the polarization properties of the scattered light-the Stokes vector components-and have the potential to be simpler to implement.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A polarization-based Thomson scattering technique for burning plasmas

2014

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The traditional Thomson scattering diagnostic is based on measurement of the wavelength spectrum of scattered light, where electron temperature measurements are inferred from thermal broadening of the scattered laser light. At sufficiently high temperatures, especially those predicted for ITER and other burning plasmas, relativistic effects cause a change in the polarization state of the scattered photons. The resulting depolarization of the scattered light is temperature dependent and has been proposed elsewhere as a potential alternative to the traditional spectral decomposition technique. Following similar work, we analytically calculate the degree of polarization for incoherent Thomson scattering. For the first time, we obtain exact results valid for the full range of incident laser polarization states and electron temperatures. While previous work focused only on linear polarization, we show that circularly polarized incident light optimizes the degree of depolarization for a wide range of temperatures relevant to burning plasmas. We discuss the feasibility of a polarization based Thomson scattering diagnostic for ITER-like plasmas with both linearly and circularly polarized light and compare to the traditional technique.

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Section: Theoretical Resultsmentioning

confidence: 99%

Section: Theoretical Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A polarization-based Thomson scattering technique for burning plasmas

2014

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“…If the degree of polarization dependence on electron temperature is accurately known from theory, the accuracy of such a diagnostic could potentially exceed that of the conventional spectrum-based TS method. First order in T m c e e 2 effects were analyzed theoretically in [6,8,9]. The most general and complete description of TS radiation is based on Mueller matrix formalism.…”

Section: Introductionmentioning

confidence: 99%

Polarization of incoherent Thomson scattering for electron temperature measurement

Mirnov

Hartog

2017

Plasma Phys. Control. Fusion

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This paper reviews the polarization properties of Thomson scattered (TS) light as applied to electron temperature measurement. The theoretical background is based on Stokes vector transformations and Mueller matrices. The review starts from scattering on a single electron and proceeds to the combined effect of many particles. Then, this general approach is subdivided into frequency-integrated and frequency-resolved applications. For each of them, the exact relativistic analytical solutions are presented in the form of Mueller matrix elements averaged over the relativistic Maxwellian distribution function. The dependencies of the elements on the scattering angle, electron temperature, and frequency of the scattered radiation (in the frequency-resolved case) are presented. These solutions form the basis for accurate analysis of the degree of depolarization of TS radiation. Results obtained for the frequency-integrated regime are reviewed and new solutions for the frequency-resolved case are reported, making a bridge between the two limiting cases. Experimental setups for polarization-based TS diagnostics are compared. A combination of polarization-based and spectral-based techniques are also described.

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“…4,5 To explore the equilibrium and perturbation of magnetic field and electron density, especially the fine structure of perturbation during MHD activity, a high resolution polarimeterinterferometer system (POLARIS) based on three-wave technique has been developed on J-TEXT tokamak. [6][7][8] To achieve this goal, J-TEXT POLARIS is intentionally developed with high phase resolution (less than 0.1 • for Faraday angle and less than 1 • for line-integrated density at 50 kHz bandwidth), high temporal resolution (<1 μs), high spatial resolution (15 mm minimum) and high spatial coverage (multiple chords covering the entire plasma cross section). In this paper the diagnostic and its application will be presented.…”

Section: Introductionmentioning

confidence: 99%

Modeling thin-film piezoelectric polymer ultrasonic sensors

González

Sorichetti

Santiago

2014

Review of Scientific Instruments

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This paper presents a model suitable to design and characterize broadband thin film sensors based on piezoelectric polymers. The aim is to describe adequately the sensor behavior, with a reasonable number of parameters and based on well-known physical equations. The mechanical variables are described by an acoustic transmission line. The electrical behavior is described by the quasi-static approximation, given the large difference between the velocities of propagation of the electrical and mechanical disturbances. The line parameters include the effects of the elastic and electrical properties of the material. The model was validated with measurements of a poly(vinylidene flouride) sensor designed for short-pulse detection. The model variables were calculated from the properties of the polymer at frequencies between 100 Hz and 30 MHz and at temperatures between 283 K and 313 K, a relevant range for applications in biology and medicine. The simulations agree very well with the experimental data, predicting satisfactorily the influence of temperature and the dielectric properties of the polymer on the behavior of the sensor. Conversely, the model allowed the calculation of the material dielectric properties from the measured response of the sensor, with good agreement with the published values.

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Polarization of radiation in incoherent Thomson scattering by high temperature plasma

Cited by 20 publications

References 6 publications

A polarization-based Thomson scattering technique for burning plasmas

A polarization-based Thomson scattering technique for burning plasmas

Polarization of incoherent Thomson scattering for electron temperature measurement

Modeling thin-film piezoelectric polymer ultrasonic sensors

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