TJ-II:Radiation asymmetries and potential variations: Difference between revisions

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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}=\left<n\right>\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>\left<...\right></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>J. M. Garcı́a-Regaña ''et al.'' ''Electrostatic potential variation on the flux surface and its impact on impurity transport'' Nuclear Fusion '''57''' 056004 (2017)</ref>
<ref>J M Garcı́a-Regaña ''et al.'' ''Electrostatic potential variation on the flux surface and its impact on impurity transport'' Nuclear Fusion submitted (2017)</ref>
have shown that <math>e\Phi_1/T_{a}</math> can take values from <math>O(0.01)</math> to <math>O(0.1)</math>. Variations are predicted to be  
have shown that <math>e\Phi_1/T_{a}</math> can take values from <math>O(0.01)</math> to <math>O(0.1)</math>. Variations are predicted to be  
larger at the outer radii than at the inner core, and stronger in ECRH plasmas than in NBI plasmas. Under
larger at the outer radii than at the inner core, and stronger in ECRH plasmas than in NBI plasmas. Under
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system <ref> M. A. Ochando ''et al.'' ''Up-down and in-out asymmetry monitoring based on broadband radiation detectors'' Fusion Sci. and Technol. '''50''' 313 (2006) </ref> after the inyection  
system <ref> M. A. Ochando ''et al.'' ''Up-down and in-out asymmetry monitoring based on broadband radiation detectors'' Fusion Sci. and Technol. '''50''' 313 (2006) </ref> after the inyection  
of some selected impurities by gas puffing is proposed. The experiment aims at studying the relation between the radially asymmetric  
of some selected impurities by gas puffing is proposed. The experiment aims at studying the relation between the radially asymmetric  
emissivity and the measured and predicted <math>\Phi_1</math> and compare this with the case where <math>\Phi_1</math> is neglected.
emissivity and the measured and predicted <math>\Phi_1</math> and compare this with the case where <math>\Phi_1</math> is neglected  
<ref> J. A. Alonso ''et al.'' ''Parallel impurity dynamics in the TJ-II stellarator'' Plasma Phys. Control. Fusion. '''58'''(7) (2016).  
<ref> J. A. Alonso ''et al.'' ''Parallel impurity dynamics in the TJ-II stellarator'' Plasma Phys. Control. Fusion. '''58'''(7) 074009 (2016)</ref>.  
The measurement and evolution of <math>\Phi_1</math> will be tracked  
The measurement and evolution of <math>\Phi_1</math> will be tracked  
during the discharges using the duplicated Langmuir probe system plasma floating potential measurements.  
during the discharges using the duplicated Langmuir probe system plasma floating potential measurements.  
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