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Nations M, Romero JA, Gupta DK, Sweeney J. High-fidelity inference of local impurity profiles in C-2W using Bayesian tomography. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:113522. [PMID: 36461419 DOI: 10.1063/5.0101741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 09/20/2022] [Indexed: 06/17/2023]
Abstract
In C-2W (also called "Norman") [1], beam-driven field reversed configuration plasmas embedded in a magnetic mirror are produced and sustained in a steady state. A multi-chord passive Doppler spectroscopy diagnostic provides line-integrated impurity emission measurements near the center plane of the confinement vessel with fast time resolution. The high degree of plasma non-uniformity across optical sightlines can preclude direct fitting of the measured line-integrated spectra. To overcome this challenge, local impurity profiles are inferred using Bayesian tomography, a superior analysis technique based on a complete forward model of the diagnostic. The measured emission of O4+ triplet lines near 278.4 nm is modeled assuming two independent populations: thermal and beam ions. Gaussian processes are used to generate and infer local profiles. The inference incorporates details of the geometrical arrangement of the diagnostic, instrument function, intensity calibration, and a noise model. Markov chain Monte Carlo (MCMC) sampling of the posterior distribution of solutions provides high-fidelity uncertainty estimates. The reconstructed O4+ impurity profiles are consistent with data from other diagnostics and show good agreement with expected physics based on previously developed models of biasing circuit and impurity transport.
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Affiliation(s)
- M Nations
- TAE Technologies, Rancho Santa Margarita, California 92688, USA
| | - J A Romero
- TAE Technologies, Rancho Santa Margarita, California 92688, USA
| | - D K Gupta
- TAE Technologies, Rancho Santa Margarita, California 92688, USA
| | - J Sweeney
- TAE Technologies, Rancho Santa Margarita, California 92688, USA
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Ramaiya N, Manchanda R, Chowdhuri MB, Yadava N, Dey R, Kumar A, Shah K, Patel S, Jadeja KA, Patel KM, Kumar R, Aich S, Pathak SK, Tanna RL, Ghosh J. Initial results from near-infrared spectroscopy on ADITYA-U tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:113552. [PMID: 36461425 DOI: 10.1063/5.0101850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 09/12/2022] [Indexed: 06/17/2023]
Abstract
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 Paβ and Paγ 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 × 1016 and 1.9 × 1016 particles cm-2 s-1 from neutral hydrogen lines Hα and Paβ, respectively, and the C influx value is found to be 3.5 × 1015 and 2.9 × 1015 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.
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Affiliation(s)
- N Ramaiya
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - R Manchanda
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - M B Chowdhuri
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - N Yadava
- Institute of Science, Nirma University, Ahmedabad 382 481, India
| | - R Dey
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - A Kumar
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - K Shah
- Department of Physics, Pandit Deendayal Energy University, Raisan, Gandhinagar 382 007, India
| | - S Patel
- Department of Physics, Pandit Deendayal Energy University, Raisan, Gandhinagar 382 007, India
| | - K A Jadeja
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - K M Patel
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - R Kumar
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - S Aich
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - S K Pathak
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - R L Tanna
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
| | - J Ghosh
- Institute for Plasma Research, Bhat, Gandhinagar 382 428, India
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Kawahata K, Peterson BJ, Akiyama T, Ashikawa N, Emoto M, Funaba H, Hamada Y, Ida K, Inagaki S, Ido T, Isobe M, Goto M, Mase A, Masuzaki S, Michael C, Morisaki T, Morita S, Muto S, Nagayama Y, Nakamura Y, Nakanishi H, Sakamoto R, Narihara K, Nishiura M, Ohdachi S, Okajima S, Osakabe M, Sakakibara S, Sanin A, Sasao M, Sato K, Shimizu A, Shoji M, Sudo S, Tamura N, Tanaka K, Toi K, Tokuzawa T, Veshchev EV, Vyacheslavov LN, Yamada I, Yoshinuma M. Overview of LHD Plasma Diagnostics. FUSION SCIENCE AND TECHNOLOGY 2010. [DOI: 10.13182/fst10-a10819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- K. Kawahata
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - B. J. Peterson
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - T. Akiyama
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - N. Ashikawa
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - M. Emoto
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - H. Funaba
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - Y. Hamada
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - K. Ida
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - S. Inagaki
- Kyushu University, Kasuga 816-8580, Japan
| | - T. Ido
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - M. Isobe
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - M. Goto
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - A. Mase
- Kyushu University, Kasuga 816-8580, Japan
| | - S. Masuzaki
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - C. Michael
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - T. Morisaki
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - S. Morita
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - S. Muto
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - Y. Nagayama
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - Y. Nakamura
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - H. Nakanishi
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - R. Sakamoto
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - K. Narihara
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - M. Nishiura
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - S. Ohdachi
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - S. Okajima
- Chubu University, Kasugai 487-8501, Japan
| | - M. Osakabe
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - S. Sakakibara
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - A. Sanin
- Budkel Institute of Nuclear Physics, Novosibirsk 630090, Russia
| | - M. Sasao
- Tohoku University, Sendai 980-8579, Japan
| | - K. Sato
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - A. Shimizu
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - M. Shoji
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - S. Sudo
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - N. Tamura
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - K. Tanaka
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - K. Toi
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - T. Tokuzawa
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - E. V. Veshchev
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | | | - I. Yamada
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
| | - M. Yoshinuma
- National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi 509-5292, Japan
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