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TJ-II:Impurity density and potential asymmetries: Difference between revisions

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TJ-II:Impurity density and potential asymmetries (view source)

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2017 Spring
2017 Spring


[[File:Photo_2018-07-20_09-32-57.jpg |thumb|right|500px| Figure 1.
Numerical vs Experiment electron-root #45477 discharge:
(a,b) Numerical impurity density asymmetry parameter <math>\alpha_{nZ}</math> and the
experimental radiation asymmetry parameter <math>\alpha_{rad}</math> respectively at the toroidal plane
<math>\phi=14.5^{\circ}</math> that corresponds the SXR toroidal measurement plane. (c,d) Numerical
impurity density asymmetry parameter <math>\alpha_{nZ}</math> and the experimental radiation asymmetry
parameter <math>\alpha_{rad}</math> respectively at the toroidal plane <math>\phi=75.5^{\circ}</math> that corresponds
the Bolometery toroidal position. Note the numerical and experimental scale sare
the same <math>[-0.38, 0.38]</math>. Since neon impurities were puffed at trave levels during the discharges, the numerical
results in (a,c) have considered <math>Z_{I}=10</math>, i.e. they have assumed fully ionization of Ne on the whole
effective radius <ref> M. Ezzat ''Advanced neoclassical impurity transport
modelling with experimental comparison for TJ-II'' Master Thesis (2018)</ref>]]
[[File:Photo_2018-07-20_09-33-36.jpg |thumb|right|500px| Figure 2. Same as in figure 1. but considering the ion-root discharge #45469 <ref> M. Ezzat ''Advanced neoclassical impurity transport
modelling with experimental comparison for TJ-II'' Master Thesis (2018)</ref>]]


== Proposal title ==
== Proposal title ==
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with <math>\theta</math> and <math>\phi</math> the poloidal and toroidal angular coordinates.  
with <math>\theta</math> and <math>\phi</math> the poloidal and toroidal angular coordinates.  
When this is taken into account the equilibrium density of the different species ''a'' present in the plasma  
When this is taken into account the equilibrium density of the different species ''a'' present in the plasma  
varies according to their adiabatic response and can be written as: <math>n_{a0}=\left<n\right>\exp\left(-Z_{a}e\Phi_1/T_{a}\right)</math>, with  
varies according to their adiabatic response and can be written as: <math>n_{a0}=\langle n\rangle\exp\left(-Z_{a}e\Phi_1/T_{a}\right)</math>, with  
<math>\left<...\right></math> the flux-surface-average. In TJ-II plasmas experiments and simulations  
<math>\langle...\rangle</math> the flux-surface-average. In TJ-II plasmas experiments and simulations  
<ref>M A Pedrosa ''et al.'', ''Electrostatic potential variations along flux surfaces in stellarators'' Nucl. Fusion '''55''' 052001 (2015) </ref>
<ref>M A Pedrosa ''et al.'', ''Electrostatic potential variations along flux surfaces in stellarators'' Nucl. Fusion '''55''' 052001 (2015) </ref>
<ref>B Liu ''et al.'' ''Direct experimental evidence of potential asymmetry in magnetic flux surfaces in stellarators'' to be submitted (2017) </ref>
<ref>B Liu ''et al.'' ''Direct experimental evidence of potential asymmetry in magnetic flux surfaces in stellarators'' to be submitted (2017) </ref>
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* The time evolution of the plasma emissivity radial profile via tomographic reconstructions of the bolometry system signals.
* The time evolution of the plasma emissivity radial profile via tomographic reconstructions of the bolometry system signals.
* The time evolution of the plasma floating potential at the outer core region (<math>r/a\sim 0.9</math>).
* The time evolution of the plasma floating potential at the outer core region (<math>r/a\sim 0.9</math>).
* The time evolution of the line-averaged density <math>\left<n_e(t)\right></math> with interferometry.
* The time evolution of the line-averaged density <math>\langle n_e(t)\rangle</math> with interferometry.
* The radial profiles of electron density <math>n_{e}(r, t_0)</math> and temperature at one time instant <math>t_0</math> using Thomson Scattering (TS).
* The radial profiles of electron density <math>n_{e}(r, t_0)</math> and temperature at one time instant <math>t_0</math> using Thomson Scattering (TS).
* The time evolution of the electron temperature profile <math>T_{e}(r,t)</math> with Electron Cyclotron Emission (ECE), when available, calibrated with TS.  
* The time evolution of the electron temperature profile <math>T_{e}(r,t)</math> with Electron Cyclotron Emission (ECE), when available, calibrated with TS.  
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== Results ==
== Results ==


[[File:Photo_2018-07-20_09-33-36.jpg |thumb|light|600px| Figure 1.
Numerical vs Experiment electron-root #45477 discharge:
(a,b) Numerical impurity density asymmetry parameter <math>\alpha_{nZ}</math> and the
experimental radiation asymmetry parameter <math>\alpha_{rad}</math> respectively at the toroidal plane
<math>\phi=14.5^{\circ}</math> that corresponds the SXR toroidal measurement plane. (c,d) Numerical
impurity density asymmetry parameter <math>\alpha_{nZ}</math> and the experimental radiation asymmetry
parameter <math>\alpha_{rad}</math> respectively at the toroidal plane <math>\phi=75.5^{\circ}</math> that corresponds
the Bolometery toroidal position. Note the numerical and experimental scale sare
the same <math>[-0.38, 0.38]</math>. Since neon impurities were puffed at trave levels during the discharges, the numerical
results in (a,c) have considered <math>Z_{I}=10</math>, i.e. they have assumed fully ionization of Ne on the whole
effective radius <ref> M. Ezzat ''Advanced neoclassical impurity transport
modelling with experimental comparison for TJ-II'' Master Thesis (2018)</ref>]]


[[File:photo_2018-07-20_09-32-57 |thumb|right|300px| Figure 1. SXR radiation for the ion-root discharge 45469 <ref> M. Ezzat ''Advanced neoclassical impurity transport
modelling with experimental comparison for TJ-II'' Master Thesis (2018)</ref>]]


== References ==
== References ==
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