Stochastic behaviour in the edge region of the SINP tokamak

Recently, there has been a great deal of importance associated with the effects of magnetic field ergodization in the dynamics of fusion grade plasmas. It is believed that ergodization of the edge magnetic fields can effectively mitigate ELMs and thus improve the confinement properties. The role of the edge electric fields has also generated a lot of interest. We have carried an experimental scan of the applied vertical magnetic field (Bv) in the S.I.N.P. tokamak, wherein an improved confinement regime has been observed. The analysis of the edge region of this set of discharges have been carried out using a Langmuir probe. Nonlinear analysis tools have been invoked to study the possibility of stochastization in the edge plasma signals. We present the results of the above experiments and analysis in this paper.