Study of magnetic levitation with a diamagnetic material for development of geophysical sensors

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04012
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 17040:Solid earth sciences-related
• Research Institution: The University of Tokyo
• Principal Investigator: Takamori Akiteru 東京大学, 地震研究所, 助教 (00372425)
• Co-Investigator(Kenkyū-buntansha): 今西 祐一 東京大学, 地震研究所, 准教授 (30260516)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 磁気浮上 / 反磁性体 / 傾斜計 / 有限要素モデル / 重力計 / 地球観測機器

Outline of Final Research Achievements

We studied magnetic levitation technique as an alternative method to conventional mechanical suspensions widely used in geophysical instruments such as seismometer, tiltmeter and gravimeters. We focused on the passive magnetic levitation that is realized by the combination of a diamagnetic material and permanent magnets. A semi-analytical model was constructed to predict dynamic behavior of levitated mass made of diamagnetic material. Based on the model, a prototype tiltmeter was designed and fabricated. The prototype tiltmeter adopted an active feedback system and the position of the levitated test mass was stabilized in a short period.
Numerical simulations of magnetic suspension in a superconducting gravimeter (SG) was performed by making a finite element model. The effectiveness of the model was successfully demonstrated by comparing its results to the observation with an existing SG.

Free Research Field

固体地球科学

Academic Significance and Societal Importance of the Research Achievements

本研究の成果は、反磁性体と永久磁石の組合わせを利用した磁気浮上方式について、その設計手法の確立と実際の装置（傾斜計）開発を通じてその実用性を示した点である。この手法の利点は、制御や超伝導状態を保つための冷却などを必要としない完全受動システムであることである。これは、消費電力やメンテナンスの観点から地球観測機器への応用として有利な特徴であるといえる。また、製作にかかるコストが低いため、観測機器を多点展開して稠密観測を行い新しい知見を得るという学術的意義だけではなく、防災に活用するという社会的意義にもつながる成果といえる。