Effect of boundary condition on chaotic behavior of fluctuation excited in electron cyclotron resonance plasma

The effect of the boundary condition on chaotic behavior of the fluctuation observed in an electron cyclotron resonance plasma is investigated by chaos analysis using measured time series data. It is found that when a stainless cage of 290 mm in diameter and 500 mm in length is introduced in the chamber, the fluctuation changes from turbulent state to chaotic state in high microwave power region while it changes from chaotic state to periodic state in low microwave power region. This result suggests that the geometry of the cage affects the state of the instability. Moreover, it is found that the superposition of multicusped fields created by small permanent magnets reduces the chaotic dimension of the instability. (author)