Visible spectroscopy of the JET pumped divertor using coherent optical‐fiber bundles

Visible spectroscopy will be one of the key diagnostics in the study of the performance of the new JET pumped divertor. Images of the divertor plasma are obtained using a periscope and coherent optical‐fiber bundle. A CCD camera records the images, using a filter to isolate the required spectral feature. The system covers the wavelength range 400–800 nm, has spatial resolution 8 mm, can detect the continuum level for all foreseen plasma operation, and has temporal resolution of up to 6 ms.