Fridge Magnets Their Structure Reveals an Interesting Pattern

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Fridge Magnets Their structure reveals an interesting pattern Image Credit: Wikipedia Materials: 1. 2 refrigerator magnets. Or 1 big enough to cut into 2 parts. The parts do not have to be equal halves. Instructions 1. Face the two magnetic surfaces towards each other . 2. Rub the magnets against each other. 3. One direction will not present a resistance. 4. Change the direction of the rub and feel the clicking resistance. 5. You are feeling the opposite pole (North and South) poles attracting and repulsing each other as the you pass one magnet over the other. A Halbach array is a special arrangement of permanent magnets that increases the magnetic field on one side of the fridge magnet, while cancelling the field to near zero on the other side. This is achieved by having a spatially rotating pattern of magnetisation. Magnets have 2 poles, North and South. North and South attract. North-North and South-South repel. The effect was discovered by John C. Mallinson in 1973, and these "one-sided flux" structures were initially described by him as a "curiosity", although at the time he recognized from this discovery the potential for Magnetic viewing film showing magnetic poles of a significant improvements in magnetic tape technology. refrigerator magnet. The poles are dark, and pole edges are bright. (Wikipedia) Physicist Klaus Halbach, while at the Lawrence Berkeley National Laboratory during the 1980s, independently invented the Halbach array to focus particle accelerator beams. (excerpt, Wikipedia) Image Author Attribution, Wikipedia Field lines around a halbach array Image author attribution, Wikipedia Questions 1. How do you know that the poles alternate on the fridge magnet? 2. Why is there no ‘clicking’ when you rub the magnets in a certain direction? 3. What would happen if all the poles lined up were either all north or all south?.

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Arxiv:1811.03898V1 [Physics.Ins-Det] 9 Nov 2018
Variable single-axis magnetic-field generator using permanent magnets Oleg Tretiak,1 Peter Blümler,1 and Lykourgos Bougas1, a) Institut fürPhysik, Johannes Gutenberg Universität-Mainz,55128 Mainz, Germany (Dated: 12 November 2018) We present a design for producing precisely adjustable and alternating single-axis magnetic fields based on nested Halbach dipole pairs consisting of permanent magnets only. Our design allows for three dimensional optical and mechanical access to a region with strong adjustable dipolar fields, is compatible with systems operating under vacuum, and does not effectively dissipate heat under normal operational conditions. We present a theoretical analysis of the properties and capabilities of our design, and construct a proof-of-concept prototype. Using our prototype, we demonstrate fields of up to several kilogauss with field homogeneities of better than 5%, which are harmonically modulated at frequencies of ∼1 Hz with a power consumption of approximately 1 W. Moreover, we discuss how our design can be modified to generate adjustable quadrupolar magnetic fields with gradients as large as 9.5 T/m in a region of optical and mechanical access. Our design is scalable and can be constructed to be suitable for table-top experiments, as in the case of polarimetric and magnetometric setups that require strong alternating magnetic fields, but also for large scale applications such as generators. Special arrangements of magnetic structures that in- crease the magnetic flux on one side of the arrangement while reducing, or even cancelling, it on the opposite side, were first theoretically proposed by Mallinson 1, but later realized by K.
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Three-Dimensional Field Solutions for Multi-Pole Cylindrical Halbach Arrays in an Axial Orientation
NASA/TM—2006-214359 Three-Dimensional Field Solutions for Multi-Pole Cylindrical Halbach Arrays in an Axial Orientation William K. Thompson Glenn Research Center, Cleveland, Ohio September 2006 NASA STI Program . in Profile Since its founding, NASA has been dedicated to the • CONFERENCE PUBLICATION. Collected advancement of aeronautics and space science. The papers from scientific and technical NASA Scientific and Technical Information (STI) conferences, symposia, seminars, or other program plays a key part in helping NASA maintain meetings sponsored or cosponsored by NASA. this important role. • SPECIAL PUBLICATION. Scientific, The NASA STI Program operates under the auspices technical, or historical information from of the Agency Chief Information Officer. It collects, NASA programs, projects, and missions, often organizes, provides for archiving, and disseminates concerned with subjects having substantial NASA’s STI. The NASA STI program provides access public interest. to the NASA Aeronautics and Space Database and its public interface, the NASA Technical Reports Server, • TECHNICAL TRANSLATION. English- thus providing one of the largest collections of language translations of foreign scientific and aeronautical and space science STI in the world. technical material pertinent to NASA’s mission. Results are published in both non-NASA channels and by NASA in the NASA STI Report Series, which Specialized services also include creating custom includes the following report types: thesauri, building customized databases, organizing and publishing research results. • TECHNICAL PUBLICATION. Reports of completed research or a major significant phase For more information about the NASA STI of research that present the results of NASA program, see the following: programs and include extensive data or theoretical analysis.
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An Adjustable Linear Halbach Array J.E
Author’s Accepted Manuscript An adjustable linear Halbach array J.E. Hilton, S.M. McMurry PII: S0304-8853(12)00100-X DOI: doi:10.1016/j.jmmm.2012.02.014 Reference: MAGMA57359 To appear in: Journal of Magnetism and Magnetic Materials www.elsevier.com/locate/jmmm Received date: 16 November 2011 Revised date: 25 January 2012 Cite this article as: J.E. Hilton and S.M. McMurry, An adjustable linear Halbach array, Journal of Magnetism and Magnetic Materials, doi:10.1016/j.jmmm.2012.02.014 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. An adjustable linear Halbach array J. E. Hiltona,∗, S. M. McMurryb aCSIRO Mathematics, Informatics and Statistics, Clayton South, VIC 3169, Australia bSchool of Physics, Trinity College Dublin, Ireland Abstract The linear Halbach array is a well known planar magnetic structure ca- pable, in the idealized case, of generating a one-sided magnetic field. We show that such a field can be created from an array of uniformly magnetized rods, and rotating these rods in an alternating fashion can smoothly transfer the resultant magnetic field through the plane of the device. We examine an idealized model composed of infinite line dipoles and carry out computa- tional simulations on a realizable device using a magnetic boundary element method.
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Inverted Linear Halbach Array for Separation of Magnetic Nanoparticles Yumi Ijiri Oberlin College, [email protected]
Oberlin Digital Commons at Oberlin Faculty & Staff choS larship 7-1-2013 Inverted Linear Halbach Array for Separation of Magnetic Nanoparticles Yumi Ijiri Oberlin College, [email protected] Chetan Poudel P. Stephen Williams Lee R. Moore Toru Orita See next page for additional authors Follow this and additional works at: https://digitalcommons.oberlin.edu/faculty_schol Repository Citation Yumi Ijiri, Chetan Poudel, P. Stephen Williams, Lee R. Moore, Toru Orita, and Maciej Zborowski. 2013. "Inverted Linear Halbach Array for Separation of Magnetic Nanoparticles." IEEE Transactions on Magnetics 49(7): 3449-3452. This Article is brought to you for free and open access by Digital Commons at Oberlin. It has been accepted for inclusion in Faculty & Staff choS larship by an authorized administrator of Digital Commons at Oberlin. For more information, please contact [email protected]. Authors Yumi Ijiri, Chetan Poudel, P. Stephen Williams, Lee R. Moore, Toru Orita, and Maciej Zborowski This article is available at Digital Commons at Oberlin: https://digitalcommons.oberlin.edu/faculty_schol/2612 IEEE TRANSACTIONS ON MAGNETICS, VOL. 49, NO. 7, JULY 2013 3449 Inverted Linear Halbach Array for Separation of Magnetic Nanoparticles Yumi Ijiri , Chetan Poudel , P. Stephen Williams ,LeeR.Moore, Toru Orita , and Maciej Zborowski Department of Physics and Astronomy, Oberlin College, Oberlin, OH 44074 USA Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195 USA Cambrian Technologies, Inc., Cleveland, OH 44109 USA A linear array of Nd-Fe-B magnets has been designed and constructed in an inverted Halbach configuration for use in separating magnetic nanoparticles. The array provides a large region of relatively low magnetic field, yet high magnetic field gradient in agree- ment with finite element modeling calculations.
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The University of Sheffield
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