TJ-II:Fast camera: Difference between revisions

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An intensified visible camera looks tangentially at a poloidal limiter where helium recycles, acting as a wide neutral source, and the atomic line emission due to plasma excitation becomes strongly localized there. It includes a bifurcated coherent bundle, each end with a different interference filter to select helium atomic lines, so that two simultaneous filtered images are captured in one single frame. The object of the proposed technique is to apply the well-known helium-beam line-ratio technique to obtain from selected filtered images the two-dimensional (2D) edge plasma n<sub>e</sub> and T<sub>e</sub>.
An intensified visible camera looks tangentially at a poloidal limiter where helium recycles, acting as a wide neutral source, and the atomic line emission due to plasma excitation becomes strongly localized there. It includes a bifurcated coherent bundle, each end with a different interference filter to select helium atomic lines, so that two simultaneous filtered images are captured in one single frame. The object of the proposed technique is to apply the well-known helium-beam line-ratio technique to obtain from selected filtered images the two-dimensional (2D) edge plasma n<sub>e</sub> and T<sub>e</sub>.


=== Limiter Recycling ===
[[File:24119.jpg|300px| link=media:24119.gif|Limiter recycling movie]]
Without filter and 75 mm lens. Speed: 54000 fps. Exposure time: 9&mu;s. V: 650 V.
ECH plasma with <n<sub>e</sub>> = 5x10<sup>18</sup> m<sup>-3</sup>.  Recycling at limiter positioned on the LCFS. The bright spot is Blackbody radiation from a glowing Langmuir probe on the limiter corner.
=== Helium Puffing ===
[[File:24080.jpg|300px|link=media:24080.gif|Helium puffing movie]]
Without filter and 75 mm lens. Speed: 100000 fps. Exposure time: 1&mu;s. V: 700 V.
ECH plasma with <n<sub>e</sub>> = 5x10<sup>18</sup> m<sup>-3</sup>.  Helium puffing through the limiter 35 mm outside LCFS.
=== Lithium emission (Li I filter) ===
[[File:18152.jpg|300px|link=media:18152.gif|Surface interaction movie]]
TJ-II plasma observed from a tangential port at 17.5 kHz sampling rate, with a lithium filter and image intensifier. In the field of view, the two most prominent areas of plasma-wall interaction can be seen:  the poloidal limiter (lower) and the hardcore (helical limiter). As the plasma transits form ECH to NBI plasmas, the interaction level diminishes and becomes predominantly centered in the limiter. <ref name="Carralero"></ref> From the lithium emission fluctuations  information on the electron density fluctuations can be gained. <ref name="delaCal"></ref>


=== Dust Visualisation <ref name="delaCal3"> </ref>===
=== Dust Visualisation <ref name="delaCal3"> </ref>===
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