Research on Behavior of Dust Particles in a Plasma under Nonuniform Magnetic Field

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K05629
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Plasma science
• Research Institution: Utsunomiya University
• Principal Investigator: Saitou Yoshifumi 宇都宮大学, 工学部, 助教 (70251080)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 微粒子プラズマ / 非一様磁場 / 帯電量 / 微粒子加速

Outline of Final Research Achievements

Behavior of dust particles in a plasma under nonuniform magnetic field, which was applied using two permanent magnets, was investigated. The followings were clarified, that is, one was the importance of the electric field for confinement, and the other was the difference in behavior brought by combinations of polarities of the magnets. Dust particles behaved as same as one magnet when the polarity was parallel. The particles were accelerated along a bisecting perpendicular line against the magnets when the polarity was antiparallel. This is useful as an acceleration mechanism of dust particles.
A simple and easy estimation method of an averaged dust charge was developed. It was found that the charge was reduced by the short mean-free-path of the ion-neutral collision when the plasma was generated using rf discharge. The charge was not reduced when the plasma was generated using hot-cathode discharge because the mean-free-path was longer.

Free Research Field

プラズマ物理

Academic Significance and Societal Importance of the Research Achievements

微粒子プラズマの物理は、宇宙物理との関連があることが指摘されている。本研究のように軸対称の非一様磁場中での振舞に関する研究はあまり存在しない。軸対称の非一様磁場は磁場を持った星の周りでの宇宙塵の振舞に関連付けられる可能性を持っている。微粒子を実験的に容易に加速できる方法を見出すことができた意義も大きい。
一方、プラズマ中の微粒子の帯電量計測にはこれまで様々な方法が用いられているが、煩雑なセッティングや解析が必要であった。本研究によって、簡単で容易な帯電量の評価方法を開発できた。微粒子プラズマの実験への貢献は少なくないと考える。