Verification that a hydrogen ionic plasma protected by a dipole magnetic field is negative-index metamaterials

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01057
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 14010:Fundamental plasma-related
• Research Institution: Yamaguchi University
• Principal Investigator: Oohara Wataru 山口大学, 大学院創成科学研究科, 教授 (80312601)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: プラズマ・核融合 / イオン性プラズマ / 左手系媒質

Outline of Final Research Achievements

The excited electrostatic waves also contained backward waves in an ionic plasma generated by irradiating hydrogen plasma across an applied magnetic field onto an Al electrode. However, it was found that, in addition to hydrogen molecular positive ions, the other molecular ions were mixed in, and electrons and H- were locally produced, accompanying the decay of the other molecular ions. Due to the undesirable presence of precursors, further elucidation of the propagation characteristics was put on hold. An Al spherical electrode simulating a magnetized asteroid was exposed to a hydrogen plasma flow simulating the solar wind. The proportion of negative ions was small in the region corresponding to Earth's Van Allen belts, and negative ions were flowing out from the polar regions along the magnetic field lines into the nightside area.

Free Research Field

プラズマ理工学

Academic Significance and Societal Importance of the Research Achievements

水素プラズマをAl電極へ照射すると水素負イオン(H-)が生成される機構は，以前から不明であった．水素化アルミ分子と予想されるプリカーサの崩壊に伴ってH-が生成されるという，新たな水素負イオン生成機構の解明が進んだ．磁化された小惑星表面付近で負イオンが生成される場合に，磁場に守られて負イオンが安定してどこに多く存在できるのかを明らかにした．独特の波動伝搬特性を持つ媒体である水素イオン性プラズマが宇宙で自然に形成され得るのか，という問いに答えようとする試みである．