Techniques for improving plasma confinement in IR-T1 Tokamak

• The effect of external fields on MHD activities and plasma confinement were investigated in IR-T1 Tokamak.
• Different techniques such as SVD and wavelet were utilized for study the magnetic fluctuations.
• Cold biased limiter with positive voltage and emissive biased limiter with negative voltage increase the plasma stability.
• The obtained results demonstrate that RHF with mode L = 3 has an effective role in plasma confinement improvement.

The main goal of this paper is the investigation of different techniques for improving the plasma confinement in IR-T1 Tokamak. For this purpose, magnetic fluctuations determined by Mirnov coils were analyzed using singular value decomposition (SVD) and wavelet techniques. Also, electric fluctuations specified by Langmuir-Ball pen probe were studied and analyzed for calculations of plasma potential and electron temperature. In this research, investigation was also made into influence of Resonant Helical Magnetic Field (RHF) (with both modes L = 2 and L = 3) on plasma stability and plasma confinement. Results show that cold biased limiter with a positive voltage and emissive biased limiter with a negative voltage were the most effective condition on increase of plasma stability and reduction of magnetic fluctuations. Also, the results demonstrated that RHF with mode L = 3 has an effective role in plasma confinement improvement.