Numerical analysis of fundamental characteristics of superconducting magnetic bearings for a polarization modulator

29th International Symposium on Superconductivity

Terachi, Yusuke^1 ; Terao, Yutaka^1 ; Ohsaki, Hiroyuki^1 ; Sakurai, Yuki^2 ; Matsumura, Tomotake^2 ; Sugai, Hajime^2 ; Utsunomiya, Shin^2 ; Kataza, Hirokazu^3 ; Yamamoto, Ryo^3

Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba

277-8561, Japan^1

Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo Institutes for Advanced Study, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba

277-8583, Japan^2

Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science (ISAS), 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa

252-5210, Japan^3

关键词: Cosmic microwave background experiments;    Density distributions;    Electromagnetic forces;    Fundamental characteristics;    Permanent magnets (PMs);    Polarization modulators;    Rotational energy-loss;    Superconducting magnetic bearings;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/871/1/012094/pdf
DOI  :  10.1088/1742-6596/871/1/012094

来源: IOP

【 摘 要 】

We have carried out numerical analysis of mechanical properties of a superconducting magnetic bearing (SMB). A contactless bearing operating at below 10 K with low rotational energy loss is an attractive feature to be used as a rotational mechanism of a polarization modulator for a cosmic microwave background experiment. In such application, a rotor diameter of about 400 mm forces us to employ a segmented magnet. As a result, there is inevitable spatial gap between the segments. In order to understand the path towards the design optimizations, 2D and 3D FEM analyses were carried out to examine fundamental characteristics of the SMBs for a polarization modulator. Two axial flux type SMBs were dealt with in the analysis: (a) the SMB with axially magnetized permanent magnets (PMs), and (b) the SMB with radially magnetized PMs and steel components for magnetic flux paths. Magnetic flux lines and density distributions, electromagnetic force characteristics, spring constants, etc. were compared among some variations of the SMBs. From the numerical analysis results, it is discussed what type, configuration and design of SMBs are more suitable for a polarization modulator.