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TJ-II:Validation of ECCD predictions in TJ-II ECRH plasmas: Difference between revisions
TJ-II:Validation of ECCD predictions in TJ-II ECRH plasmas (view source)
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== Experimental campaign == | == Experimental campaign == | ||
2018 | 2018 Autumn | ||
== Proposal title == | == Proposal title == | ||
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== Name and affiliation of proponents == | == Name and affiliation of proponents == | ||
J. M García Regaña<sup>1</sup>, Á. Cappa<sup>1</sup>, A. Gozález-Jeréz<sup>2</sup>, A. López-Fraguas<sup>1</sup>, N. B. Marushchenko, ... <sup>3</sup> and TJ-II team<sup>1</sup>. | |||
== Background == | == Background == | ||
[[File:ECCD_Travis_A_Gonzalez_Jerez.jpg |thumb|right|300px| Figure 1. Total toroidal current ECCD as a function of <math>N_{\|}</math> calculated for the TJ-II | [[File:ECCD_Travis_A_Gonzalez_Jerez.jpg |thumb|right|300px| Figure 1. Total toroidal current ECCD as a function of <math>N_{\|}</math> calculated for the TJ-II transmission line QTL2 with the code TRAVIS.]] | ||
The current driven by means of EC waves, so-called Electron Cyclotron Current Drive (ECCD), has been proposed as a tool | The current driven by means of EC waves, so-called Electron Cyclotron Current Drive (ECCD), has been proposed as a tool | ||
for non-inductive current induction in tokamaks, as well as a mean of current control and tailoring of the rotational transform <math>\iota</math> in stellarators. | for non-inductive current induction in tokamaks, as well as a mean of current control and tailoring of the rotational transform <math>\iota</math> in stellarators. | ||
In particular, it can modify through its impact on <math>\iota</math> the map of Alfvén eigenmode (AE) and with it the fast ion dynamics. | In particular, it can modify through its impact on <math>\iota</math> the map of Alfvén eigenmode (AE) and with it the fast ion dynamics. | ||
In view of future studies of AE-induced fast ion losses in TJ-II the present proposal focuses on the validation of the | In view of future studies of AE-induced fast ion losses in TJ-II the present proposal focuses on extending the present the validation of the | ||
ECCD predictions comparing these with the experimental values. | ECCD predictions comparing these with the experimental values. The available comparison considering past campaigns data and recent TRAVIS simulations | ||
find strong disagreements that suggest that corrections on the polarization of the incident wave, beam focusing and other factors leads to a | |||
numerical overestimation on the ECH power source on the numerical estimate. Hence the present experiment aims at measuring the | |||
induced ECCD together with the estimation of the experiment power source measured by means of modulated EC heating and confirming | |||
the modifications on the rotational transform obtained with VMEC. | |||
== | == Experiment planning and required resources == | ||
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The required signals to perform the analysis are: | The required signals to perform the analysis are: | ||
* The time evolution of the toroidal plasma current. | * The time evolution of the toroidal plasma current with the Rogowski coils. | ||
* The Motional Stark Effect looking at an inner core radial position <math>r/a\approx 0.2</math>, to check for possible changes on the rotational transform. | |||
* 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>\left<n_e(t)\right></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). | ||
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== Preferred dates and degree of flexibility == | == Preferred dates and degree of flexibility == | ||
Preferred dates: due to the availability on-site of the proponents the experimental days should fall out of the calender week 14. | Preferred dates: due to the availability on-site of the proponents the experimental days should fall out of the calender week 14. | ||
A valuable input for this experiment regarding the L/R time at similar conditions in the absence of ECCD may result from the conduction of the experimental proposal "Validation of bootstap predictions" (http://fusionwiki.ciemat.es/wiki/TJ-II:Validation_of_bootstrap_predictions). Thus, the present proposal shall be preferably scheduled after that proposal. | |||
<hr> | |||
[[TJ-II:Experimental proposals|Back to list of experimental proposals]] | |||
[[Category:TJ-II internal documents]] | |||
[[Category:TJ-II experimental proposals Autumn 2018]] | |||