DOE OSTI · 3014101
Transient plasma-detachment events induced by multiple gas puffs in ADITYA-U tokamak
Abstract
Application of periodic short bursts of gas leads to periodic separation of the plasma column edge from the limiter in the Ohmically heated discharges of ADITYA-U tokamak. After every gas-puff, injecting around 10 17 –10 18 m −3 molecules of fuel gas in the edge of the plasma column, a significant reduction in plasma density, temperature, H α emission intensity and an increase in the H β /H α ratio is observed in the vicinity of the limiter radius for a certain time duration before these parameters regain their pre-gas puff values. A decline in the ion-flux to the limiter is also observed simultaneously. The global confinement of plasma also increases after each gas-puff. These observations, which repeat after each gas-injection, imply that the plasma–neutral interaction occurs further away from the limiters after the gas-injection and indicate a periodic plasma separation from the limiter surface. Further investigation revealed that the gas-injection modifies the radial and toroidal electric field, which may be playing a role in the separation of the plasma column from the limiter surface. It was further demonstrated by an electrode bias experiment in the absence of gas-injection that an application of an external radial electric field can result in obtaining a separated plasma state.
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Dolui, Suman [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0000000166934584), Singh, Kaushlender [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0000000293157706), Macwan, Tanmay [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)] (ORCID:0000000297670830), Aich, Suman [Institute for Plasma Research (IPR), Gandhinagar (India)], Raj, Harshita [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0000000167781292), Gautam, P. [Institute for Plasma Research (IPR), Gandhinagar (India)], Kumawat, Devilal [Institute for Plasma Research (IPR), Gandhinagar (India)] (ORCID:0000000155660688), Kumar, Ankit [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0009000164575845), Kumawat, Ashok K. [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0009000185496548), Hegde, Bharat [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0009000196748552), Yadava, Nandini [Oak Ridge Associated Universities (ORAU), Oak Ridge, TN (United States)] (ORCID:0000000155222450), Patel, Sharvil [Univ. of Virginia, Charlottesville, VA (United States)] (ORCID:0000000231127114), Bose, Subhojit [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0000000337632071), Hoque, Injamul [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0009000296677747), Banerjee, Soumitra [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0009000226768117), Yadav, Komal [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0009000405885407), Jadeja, K. A. [Institute for Plasma Research (IPR), Gandhinagar (India)] (ORCID:0000000206770079), Patel, K. M. [Institute for Plasma Research (IPR), Gandhinagar (India)] (ORCID:0000000284060267), Kumar, Rohit [Institute for Plasma Research (IPR), Gandhinagar (India)] (ORCID:0000000197760468), Chowdhuri, M. B. [Institute for Plasma Research (IPR), Gandhinagar (India)] (ORCID:0000000183131089), Dey, Ritu [Institute for Plasma Research (IPR), Gandhinagar (India)] (ORCID:0000000176650497), Nagora, Umesh [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0000000255490444), Tahiliani, K. [Institute for Plasma Research (IPR), Gandhinagar (India)] (ORCID:000000022791537X), Pathak, S. K. [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0000000223342455), Chattopadhyay, P. K. [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0009000868862789), Sen, A. [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0000000198784330), Saxena, Y. C. [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0000000250841065), Pal, R. [Saha Institute of Nuclear Physics, Kolkata (India)], Tanna, R. L. [Institute for Plasma Research (IPR), Gandhinagar (India)] (ORCID:0000000346137072), Ghosh, J. [Institute for Plasma Research (IPR), Gandhinagar (India); Homi Bhabha National Institute (HBNI), Mumbai (India)] (ORCID:0000000243691900). 2025-10-14. Transient plasma-detachment events induced by multiple gas puffs in ADITYA-U tokamak. https://doi.org/10.1063/5.0286193
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