[PEPPo] interesting solenoid article

[Jay Benesch]

Volker's article via arxiv

https://arxiv.org/abs/2106.14676
Strap-on magnets: a framework for rapid prototyping of magnets and beam 
lines
Volker Ziemann
We describe a framework to assemble permanent-magnet cubes in 3D-printed 
frames to construct dipole, quadrupole, and solenoid magnets, whose 
field, in the absence of iron, can be calculated analytically in three 
spatial dimensions. Rotating closely spaced dipoles and quadrupoles in 
opposite directions allows us to adjust the integrated strength of a 
multipole. Contributions of unwanted harmonics are calculated and found 
to be moderate. We then combine multiple magnets to construct beam-line 
modules: chicane, triplet cell, and solenoid focusing system.

https://arxiv.org/abs/2207.09911
Magnetic Field of a Permanent Magnet
David Shulman
For magnetic field calculations, cylindrical permanent magnets are often 
approximated as ideal, azimuthally symmetric solenoids. Despite the 
frequent usage of this approximation, research papers demonstrating the 
validity and limitations of this approach are scarcely available. In 
this paper, the experimentally derived magnetic field of a cylindrical 
permanent magnet is compared with the analytically calculated magnetic 
field of an ideal solenoid. An experimental setup for measuring the 
magnetic field distribution is demonstrated and employed for gathering 
the data. The proposed setup allows to measure the distributions of the 
axial and radial components of the magnetic field surrounding the 
magnet. The experimental data is in a very good agreement with the 
theoretical predictions, confirming the validity of using the model of 
an ideal solenoid for predicting a magnetic field distribution of a 
permanent magnet.

https://arxiv.org/abs/2305.17227
Practical Concepts for Design, Construction and Application of Halbach 
Magnets in Magnetic Resonance
Peter Blümler, Helmut Soltner
This review is a compilation of relevant concepts in designing Halbach 
multipoles for magnetic resonance applications. The main focus is on 
providing practical guidelines to plan, design and build such magnets. 
Therefore, analytical equations are presented for estimating the 
magnetic field from ideal to realistic systems. Various strategies of 
homogenizing magnetic fields are discussed together with concepts of 
opening such magnets without force, or combining them for variable 
fields. Temperature compensation and other practical aspects are also 
reviewed. For magnetic resonance two polarities (di- and quadrupole) are 
of main interest, but higher polarities are also included.
Comments:	39 pages, 17 Figures