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Oct 13 – 18, 2014
Hotel Park Inn Pribaltiyskaya
Europe/Moscow timezone

Recent ICRH-Wall Conditioning, Second Harmonic Heating and Disruption Mitigation Experiments Using ICRH System in Tokamak ADITYA

Oct 17, 2014, 8:30 AM
4h
Green 8-9 (Hotel Park Inn Pribaltiyskaya)

Green 8-9

Hotel Park Inn Pribaltiyskaya

Saint Petersburg, Russian Federation
Poster Poster 7

Speaker

Dr Sanjay Kulkarni (Institute for Plasma Research)

Description

ADITYA is a medium size tokamak with major radius 0.75 m and minor radius of 0.25 m, with toroidal magnetic field up to 1.5 T and has circular plasma in hydrogen gas. The diagnostics used in ICRH experiments are Langmuir probes, visible camera, spectroscopy, soft X-ray and hard X-ray detection techniques, diamagnetic loop, heterodyne on-line density measurements, Thompson scattering, Neutral particle analyzer, Limiter thermography, Residual Gas Analyzer(RGA), microwave diagnostics along with normal machine diagnostics like loop voltage, position and plasma current measurements. The indigenously developed ICRH system is installed on ADITYA having 1 MW RF generator in the frequency range of 20-40 MHz, transmission line with matching system, vacuum interface and fast wave poloidal type antenna with Faraday shield. Here we report the recent experiments carried out on tokamak ADITYA using the developed ICRH system of 1 MW at 24.8 MHz frequency. The experiments are carried out to have plasma heating at second harmonic, disruption mitigation and also wall conditioning in presence of toroidal magnetic field. The wall conditioning experiments are carried out in presence of toroidal magnetic field under resonant (0.75T), non-resonant (0.45 T) conditions as well as with 20% He gas in a hydrogen plasma (0.45T). All three sets are found more effective in releasing wall impurities like water & methane as half an order (~ 5) of initial vacuum condition. As per data, the resonant ICWC is more effective to reduce carbon impurity and non-resonant ICWC is more effective to reduce oxygen impurity from vessel. The heating experiments at second harmonic are carried out using RF pulses of different magnitudes (5 ms-100 ms) at different RF powers (40 kW-200 kW) in plasma duration of 100 ms. The soft X-ray data shows an electron temperature rise from 250 eV to maximum of 500 eV and NPA data as well data from Doppler broadening shows the ion temperature rise up to 350 eV. In order to carry out mitigation of disruptions induced by hydrogen gas puff, ICRH system was used in both fixed and real time feedback mode. In an attempt to control the disruptions in real time the gas-puff induced H intensity increase is used as a precursor for the disruption and mitigation is successfully carried out.
Paper Number EX/P7-16
Country or International Organisation India

Primary author

Dr Sanjay Kulkarni (Institute for Plasma Research)

Co-authors

Prof. Ajai Kumar (Institute for Plasma Research) Mr Ajay Kumar (Institute for Plasma Research) Prof. Amita Das (Institute for Plasma Research) Mr Atul Varia (Institute for Plasma Research) Mr Bhavesh Kadia (Institute for Plasma Research) Mr Chetnarayan Gupta (Institute for Plasma Research) Prof. Dhiraj Bora (Institute for Plasma Research) Ms Gayatri Ashok (Institute for Plasma Research) Mr Hiralal Jadav (Institute for Plasma Research) Mr Jayesh Raval (Institute for Plasma Research) Mr Jinto Thomas (Institute for Plasma Research) Dr Joydeep Ghosh (Institute for Plasma Research) Ms Kanchan Mahavar (Institute for Plasma Research) Mr Kirit Parmar (Institute for Plasma Research) Mr Kumar Jadeja (Institute for Plasma Research) Dr Malay Chowdhuri (Institute for Plasma Research) Dr Manoj Gupta (Institute for Plasma Research) Mr Manoj Parihar (Institute for Plasma Research) Ms Nilam Ramaiya (Institute for Plasma Research) Ms Niral Patel (Institute for Plasma Research) Dr Prabal Chattopadhyaya (Institute for Plasma Research) Mr Praveenlal E V (Institute for Plasma Research) Mr Pravinkumar Atrey (Institute for Plasma Research) Prof. Predhiman Kaw (Institute for Plasma Research) Mr Rakesh Tanna (Institute for Plasma Research) Mr Ramesh Joshi (Institute for Plasma Research) Mr Ranapratap Yadav (Institute for Plasma Research) Mrs Ranjana Manchanda (Institute for Plasma Research) Prof. Ratneshwar Jha (Institute for Plasma Research) Mr Sameerkumar Jha (Institute for Plasma Research) Dr Santanu Banerjee (Institute for Plasma Research) Mr Santosh Pandya (Institute for Plasma Research) Mr Shailesh Bhatt (Institute for Plasma Research) Mr Shankar Joisa (Institute for Plasma Research) Mrs Snehlata Gupta (Institute for Plasma Research) Mr Sunil kumar (Institute for Plasma Research) Dr Suryakant Pathak (Institute for Plasma Research) Mr Umesh Dhobi (Institute for Plasma Research) Mr YSS Srinivas (Institute for Plasma Research)

Presentation materials