Especially in the case of magnetic fields, calculations are time consuming and often impossible due to the required spatial resolution. Therefore, the magnetic fields have to be measured, these measurements are very time consuming too and the needed spatial resolution cannot be obtained.
Higher order interpolation schemes are needed because of these problems. Several interpolation procedures are known for the described magnetic field (rotation and divergence free) in absence of conducting currents and in a homogenous material. As stated in the publication, these have limitations such as not reaching the required accuracy or needing a large number of grid points. In general, these methods result in a field in the grid with finite divergence and rotation, which could possibly lead to unphysical results. These inadequacies can be remedied with the suggested new procedure: a divergence and rotation free interpolation of a vector field inside a 3D-rectangular grid, with an accuracy that is third order in grid size.
When you are interested in the complete methods, results and other conclusions, we recommend you to read the whole publication or contact us. This way knowledge acquired in 2013, can be used in 2018 to conduct further research.