arXiv subjects

Mayuko Koga

Publications and source records attributed to Mayuko Koga.

2 recordsLinked to original sources

arXiv2004

Control of fluctuations in ECR plasma by applying multipole magnetic fields

The control of fluctuations generated in an electron cyclotron resonance (ECR) plasma is attempted by changing microwave powers. It is found that when a cage is introduced in the vacuum chamber, the fluctuations change from turbulent state to chaotic state in the high microwave power region while it changes from chaotic state to periodic state in the 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. When pulsed multipole magnetic fields are also added to external magnetic fields, the fluctuations are suppressed.

physics.plasm-ph↗

arXiv2004

Production of a large diameter ECR plasma for plasma processing

A large diameter plasma over 300 mm in diameter is produced by electron cyclotron resonance (ECR) discharges using a newly developed large diameter chamber of 400 mm in inner diameter. It is found that the electron temperature decreases as nitrogen gas is added to pure argon plasma, which is considered that nitrogen molecules absorb the electron energy into the vibrational energy and lead to the decrease of the electron temperature. Moreover, it is found that the plasma uniformity is improved by adding nitrogen gas, suggesting that the adjunction of nitrogen gas is effective for producing uniform and low electron temperature plasma.

physics.plasm-ph↗