Nuclear Fusion (Jan 2024)

Micro-particle injection experiments in ADITYA-U tokamak using an inductively driven pellet injector

  • Sambaran Pahari,
  • Rahulnath P.P.,
  • Aditya Nandan Savita,
  • Pradeep Kumar Maurya,
  • Saroj Kumar Jha,
  • Neeraj Shiv,
  • Raghavendra K.,
  • Harsh Hemani,
  • Belli Nagaraju,
  • Sukantam Mahar,
  • Manmadha Rao,
  • I.V.V. Suryaprasad,
  • U.D. Malshe,
  • J. Ghosh,
  • B.R. Doshi,
  • Prabal Kumar Chattopadhyay,
  • R.L. Tanna,
  • K.A. Jadeja,
  • K.M. Patel,
  • Rohit Kumar,
  • Tanmay Macwan,
  • Harshita Raj,
  • S. Aich,
  • Kaushlender Singh,
  • Suman Dolui,
  • D. Kumawat,
  • M.N. Makwana,
  • K.S. Shah,
  • Shivam Gupta,
  • V. Balakrishnan,
  • C.N. Gupta,
  • Swadesh Kumar Patnaik,
  • Praveenlal Edappala,
  • Minsha Shah,
  • Bhavesh Kadia,
  • Nandini Yadava,
  • Kajal Shah,
  • G. Shukla,
  • M.B. Chowdhuri,
  • R. Manchanda,
  • Nilam Ramaiya,
  • Manoj Kumar,
  • Umesh Nagora,
  • Varsha S.,
  • S.K. Pathak,
  • Kumudni Asudani,
  • Paritosh Chaudhuri,
  • P.N. Maya,
  • Rajiv Goswami,
  • A. Sen,
  • Y.C. Saxena,
  • R. Pal,
  • S. Chaturvedi

DOI
https://doi.org/10.1088/1741-4326/ad2b5f
Journal volume & issue
Vol. 64, no. 5
p. 056007

Abstract

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A first-of-its-kind, inductively driven micro-particle (Pellet) accelerator and injector have been developed and operated successfully in ADITYA-U circular plasma operations, which may ably address the critical need for a suitable disruption control mechanism in ITER and future tokamak. The device combines the principles of electromagnetic induction, pulse power technology, impact, and fracture dynamics. It is designed to operate in a variety of environments, including atmospheric pressure and ultra-high vacuum. It can also accommodate a wide range of pellet quantities, sizes, and materials and can adjust the pellets’ velocities over a coarse and fine range. The device has a modular design such that the maximum velocity can be increased by increasing the number of modules. A cluster of lithium titanate/carbonate (Li _2 TiO _3 /Li _2 CO _3 ) impurity particles with variable particle sizes, weighing ∼50–200 mg are injected with velocities of the order of ∼200 m s ^−1 during the current plateau in ADITYA-U tokamak. This leads to a complete collapse of the plasma current within ∼5–6 ms of triggering the injector. The current quench time is dependent on the amount of impurity injected as well as the compound, with Li _2 TiO _3 injection causing a faster current quench than Li _2 CO _3 injection, as more power is radiated in the case of Li _2 TiO _3 . The increase in radiation due to the macro-particle injection starts in the plasma core, while the soft x-ray emission indicates that the entire plasma core collapses at once.

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