| Autor: |
Maragkoudakis, E., Carralero, D., Estrada, T., Windisch, T., Gao, Y., Killer, C., Jakubowski, M., Sitjes, A. Puig, Pisano, F., Sándor, H., Vecsei, M., Zoletnik, S., Cappa, A., team, the Wendelstein 7-X |
| Rok vydání: |
2022 |
| Předmět: |
|
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1088/1741-4326/aca6fa |
| Popis: |
The formation of the radial electric field, $E_{\rm r}$ in the SOL has been experimentally studied for attached divertor conditions in stellarator W7-X. The main objective of this study is to test the validity in a complex 3D island divertor of simple models, typically developed in tokamaks, relating $E_{\rm r}$ to the sheath potential drop gradient at the target. Additionally, we investigate the effect of the edge $E_{\rm r}$ shear on the reduction of density fluctuation amplitude, a well-established phenomenon according to the existing bibliography. The main diagnostic for measurements in the SOL is a V-band Doppler reflectometer that can provide the measurement of the $E_{\rm r}$ and density fluctuations with good spatial resolution. Three-dimensional measurements of divertor parameters has been carried out using infrared cameras, with $\lambda_{\rm q}$ resulting a suitable proxy for the model-relevant $\lambda_{\rm T}$. In the investigated attached regimes, it is shown for the first time that the formation of the $E_{\rm r}$ in the SOL depends on parameters at the divertor, following a $E_{\rm r} \propto T_{\rm e} /\lambda_q$ qualitatively similar to that found in a tokamak. Then, from the analyzed plasmas, the observed $E_{\rm r}$ shear at the edge is linked to a moderate local reduction of the amplitude of density fluctuations. |
| Databáze: |
arXiv |
| Externí odkaz: |
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