Openable Force-Balanced Halbach Magnets : From Fibonacci Sphere Simulations to Icosahedral Realizations

Title data

Rehberg, Ingo ; Soltner, Helmut ; Blümler, Peter:
Openable Force-Balanced Halbach Magnets : From Fibonacci Sphere Simulations to Icosahedral Realizations.
arXiv
USA , 2026
DOI: https://doi.org/10.48550/arXiv.2608.09323

Official URL:

Abstract in another language

A long-standing goal in magnet design is to completely surround a volume of highly homogeneous magnetic field with permanent magnets while maintaining practical access to that volume. In this work, we present a theoretical and experimental investigation of mechanically accessible spherical magnets in Halbach configuration that can be opened with minimal or vanishing force. Focusing on dipolar Halbach spheres composed of discrete magnetic subunits, we derive conditions for force-free opening along specific cutting planes. These conditions define a continuous set of geometries for which tensile magnetic forces cancel, leaving only shear components, enabling mechanically effortless opening. The theoretical predictions are validated experimentally using icosahedral approximations of the Halbach sphere, for which both opening forces and magnetic field properties are measured. The results demonstrate that excellent field homogeneity can be preserved while reducing opening forces by orders of magnitude. Although discussed in detail for the dipolar case, the theoretical framework is general and applicable to higher-order multipole Halbach systems. Finally, the concepts are extended to spherocylindrical Halbach configurations, highlighting their potential for large-volume, highly homogeneous, and mechanically accessible permanent-magnet systems for magnetic resonance

Further data

Item Type:	Preprint, postprint
Institutions of the University:	Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Former Professors > Chair Experimental Physics V - Univ.-Prof. Dr. Ingo Rehberg Profile Fields > Advanced Fields > Nonlinear Dynamics
Result of work at the UBT:	Yes
DDC Subjects:	500 Science > 530 Physics
Date Deposited:	17 Aug 2026 10:15
Last Modified:	17 Aug 2026 10:15
URI:	https://eref.uni-bayreuth.de/id/eprint/99275