| Autor: |
Ramaiya N; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India., Manchanda R; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India., Chowdhuri MB; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India., Yadava N; Institute of Science, Nirma University, Ahmedabad 382 481, India., Dey R; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India., Kumar A; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India., Shah K; Department of Physics, Pandit Deendayal Energy University, Raisan, Gandhinagar 382 007, India., Patel S; Department of Physics, Pandit Deendayal Energy University, Raisan, Gandhinagar 382 007, India., Jadeja KA; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India., Patel KM; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India., Kumar R; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India., Aich S; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India., Pathak SK; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India., Tanna RL; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India., Ghosh J; Institute for Plasma Research, Bhat, Gandhinagar 382 428, India. |
| Abstrakt: |
Spectroscopy in vacuum ultraviolet (VUV) and visible ranges plays an important role in the investigation and diagnosis of tokamak plasmas. However, under harsh environmental conditions of fusion grade devices, such as ITER, VUV-visible systems encounter many issues due to the degradation of optical components used in such systems. Here, near-infrared (NIR) spectroscopy has become an effective tool in understanding the edge plasma dynamics. Considering its importance, a NIR spectroscopic diagnostic has been developed and installed on the ADITYA-U tokamak. The system consists of a 0.5 m spectrometer having three gratings with different groove densities, and it is coupled with a linear InGaAs photodiode array. Radiation from the ADITYA-U edge plasma has been collected using a collimating lens and optical fiber combination and transported to the spectrometer. The spectrum in the NIR range from the ADITYA-U plasma has been recorded using this system, in which Pa β and Pa γ along with many spectral lines from neutral and singly ionized impurities have been observed. The influxes of H and C have been estimated from measurements. The H influx value is found to be 2.8 × 10 16 and 1.9 × 10 16 particles cm -2 s -1 from neutral hydrogen lines H α and Pa β , respectively, and the C influx value is found to be 3.5 × 10 15 and 2.9 × 10 15 particles cm -2 s -1 from the neutral carbon and singly ionized carbon, respectively. A good agreement is seen between these results and the results obtained by using a routine photomultiplier tube based diagnostic. |
