MHD activity induced coherent mode excitation in the edge plasma region of ADITYA-U tokamak
In this paper, we report the excitation of coherent density and potential fluctuations induced by magnetohydrodynamic (MHD) activity in the edge plasma region of ADITYA-U tokamak. When the amplitude of the MHD mode, mainly the m/n = 2/1, increases beyond a threshold value, |B̃θ|/Bθ ∼ 0.3%–0.4%, coherent oscillations in the density and potential fluctuations are observed having the same frequency as that of the MHD mode. The mode numbers of these MHD induced density and potential fluctuations are obtained by Langmuir probes placed at different radial, poloidal, and toroidal locations in the edge plasma region. Detailed analyses of these Langmuir probe measurements reveal that the coherent mode in edge potential fluctuation has a mode structure of m/n = 2/1, whereas the edge density fluctuation has an m/n = 1/1 structure. It is further observed that beyond the threshold, the coupled power fraction scales almost linearly with the magnitude of B̃θ/Bθ fluctuations. Furthermore, the rise rates of the coupled power fraction for coherent modes in density and potential fluctuations are also found to be dependent on the growth rate of magnetic fluctuations. The disparate mode structures of the excited modes in density and plasma potential fluctuations suggest that the underlying mechanism for their existence is the coupling of even harmonics of potential to the odd harmonics of pressure due to 1/R dependence of the toroidal magnetic field.
Authors
- Sharvil Patel (ORCID: https://orcid.org/0000-0002-3112-7114)
- Suman Dolui (ORCID: https://orcid.org/0000-0001-6693-4584)
- Komal Yadav (ORCID: https://orcid.org/0009-0004-0588-5407)
- D. Raju (ORCID: https://orcid.org/0000-0002-2183-7841)
- Ankit Patel (ORCID: https://orcid.org/0000-0001-6812-1464)
- Kalpesh Galodiya
- Rohit Kumar (ORCID: https://orcid.org/0000-0001-9776-0468)
- Laxmikanta Pradhan
- Tanmay Macwan (ORCID: https://orcid.org/0000-0002-9767-0830)
- Suman Aich (ORCID: https://orcid.org/0000-0003-3561-9180)
- Abha Kanik (ORCID: https://orcid.org/0009-0001-1906-7438)
- Y. C. Saxena (ORCID: https://orcid.org/0000-0002-5084-1065)
- Pramila Gautam (ORCID: https://orcid.org/0009-0003-2187-6925)
- Shwetang N. Pandya (ORCID: https://orcid.org/0000-0003-4346-8036)
- Rakesh L. Tanna (ORCID: https://orcid.org/0000-0003-4613-7072)
- Kaushlender Singh (ORCID: https://orcid.org/0000-0002-9315-7706)
- Joydeep Ghosh (ORCID: https://orcid.org/0000-0002-4369-1900)
- Prabal Kumar Chattopadhyay (ORCID: https://orcid.org/0009-0008-6886-2789)
- Harshita Raj (ORCID: https://orcid.org/0000-0001-6778-1292)
- Lavkesh Lachhvani (ORCID: https://orcid.org/0000-0003-4886-8514)
- Ashok K. Kumawat
- Ankit Kumar (ORCID: https://orcid.org/0009-0001-6457-5845)
- Abhijit Sen (ORCID: https://orcid.org/0000-0001-9878-4330)
- K.A. Jadeja (ORCID: https://orcid.org/0000-0002-0677-0079)
- Sameer Kumar (ORCID: https://orcid.org/0000-0001-5826-615X)
- K.M. Patel (ORCID: https://orcid.org/0000-0002-8406-0267)
- Injamul Hoque (ORCID: https://orcid.org/0009-0002-9667-7747)
- Bharat Hegde (ORCID: https://orcid.org/0009-0001-9674-8552)
- Soumitra Banerjee
- R. Pal (ORCID: https://orcid.org/0009-0005-0759-3448)
- M. B. Chaudhary
Institutions
- Saha Institute of Nuclear Physics (IN)
- University of California, Los Angeles (US)
- Nirma University (IN)
- Saurashtra University (IN)
- Homi Bhabha National Institute (IN)
- Pandit Deendayal Energy University (IN)
- Institute for Plasma Research (IN)
- University of Petroleum and Energy Studies (IN)
Publication Details
- Journal
- Physics of Plasmas
- Published
- 2024-09-01
- DOI
- https://doi.org/10.1063/5.0218952
- Citations
- 6
- Primary Topic
- Magnetic confinement fusion research
- Type
- article
- Field-Weighted Citation Impact
- 3.96