Formation of electron-positron plasma using a levitated dipole magnetic configuration and intense slow positron beam(Fostering Joint International Research)

• Project/Area Number: 16KK0094
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research)
• Allocation Type: Multi-year Fund
• Research Field: Plasma science
• Research Institution: The University of Tokyo
• Principal Investigator: Saitoh Haruhiko 東京大学, 大学院新領域創成科学研究科, 准教授 (60415164)
• Project Period (FY): 2017 – 2020
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥15,080,000 (Direct Cost: ¥11,600,000、Indirect Cost: ¥3,480,000)
• Keywords: 反物質 / 陽電子 / 電子陽電子プラズマ / ペアプラズマ / ダイポール磁場 / 磁気圏型閉じ込め / 反物質プラズマ / 非中性プラズマ / プラズマ・核融合 / 低速陽電子ビーム

Outline of Final Research Achievements

Pair plasmas consisting of electrons and positrons, the antiparticles of electrons, are predicted to show unique properties when compared with ion electron plasmas with large mas ratios. The electron-positron plasmas are also important in astrophysical phenomena. In this study, we conducted investigation toward the experimental realization of electron positron plasmas by using intense slow positron source in Technical University of Munich and dipole magnetic field configuration. In a compact dipole magnetic trap, efficient (approximately 100%) injection, relatively long time (longer than 1s) trapping, and orbit compression with rotating wall electric field were realized in experiments with positron beam. High density state of electrons and positrons to satisfy the plasma condition in a superconducting configuration was not realized in this research period.

Academic Significance and Societal Importance of the Research Achievements

パルサー等の高エネルギー天体周辺に存在すると考えられている電子陽電子プラズマの性質の解明は，天体現象の理解のために，また核融合等の様々な応用を持つプラズマ物理の進展への寄与の観点からも重要である．本研究では，実験的に電子陽電子プラズマを実現する上で鍵となる，高い効率で陽電子ビームを閉じ込め装置に入射する方法と，安定な閉じ込めを実現した．回転電場をダイポール磁場中で初めて適用し，反物質プラズマの高密度状態を実現するための原理検証がなされた．最終的な研究目標である電子陽電子プラズマ生成には至らなかったが，提案した手法により反物質閉じ込めが可能であることが示され，重要な段階の幾つかが解決された．

Research Products

• [Int'l Joint Research] マックスプランク・プラズマ物理研究所 (IPP)(ドイツ) (2017)
  • Year and Date: 2017-04-18
• [Int'l Joint Research] ミュンヘン工科大学 (TUM)(ドイツ) (2017)
  • Year and Date: 2017-04-18
• [Journal Article] Positron orbit effects during injection and confinement in a magnetic dipole trap (2020)
  • Author(s): S. Nissl, E.V. Stenson, U. Hergenhahn, J. Horn-Stanja, T. Sunn Pedersen, H. Saitoh, C. Hugenschmidt, M. Singer, M.R. Stoneking, J.R. Danielson
  • Journal Title: Physics of Plasmas Volume: 27 Issue: 5 Pages: 0521071-10
  • DOI: 10.1063/5.0007252
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A new frontier in laboratory physics: magnetized electron?positron plasmas (2020)
  • Author(s): M.R. Stoneking, T. Sunn Pedersen, P. Helander, H. Chen, U. Hergenhahn, E.V. Stenson, G. Fiksel, J. von der Linden, H. Saitoh, C.M. Surko, J.R. Danielson, C. Hugenschmidt, J. Horn-Stanja, A. Mishchenko, D. Kennedy, A. Deller, A. Card, S. Nissl, M. Singer, S. Koenig, L. Willingale, J. Peebles, M.R. Edwards, K. Chin
  • Journal Title: Journal of Plasma Physics Volume: 86 Issue: 6 Pages: 1558606011-26
  • DOI: 10.1017/s0022377820001385
  • Peer Reviewed / Int'l Joint Research
• [Presentation] 高温超伝導小型巻線を用いたダイポール磁場荷電粒子トラップの開発計画 (2020)
  • Author(s): 齋藤晴彦, 谷岡樹，西浦正樹，吉田善章
  • Organizer: 物理学会第2021年年次大会