In this paper a novel compressor for static magnetic fields is proposed based on finite embedded transformation optics. When the DC magnetic field passes through the designed device, the magnetic field can be compressed inside the device. After it passes through the device, one can obtain an enhanced static magnetic field behind the output surface of the device (in a free space region). We can also combine our compressor with some other structures to get a higher static magnetic field enhancement in a free space region. In contrast with other devices based on transformation optics for enhancing static magnetic fields, our device is not a closed structure and thus has some special applications (e.g., for controlling magnetic nano-particles for gene and drug delivery). The designed compressor can be constructed by using currently available materials or DC meta-materials with positive permeability. Numerical simulation verifies good performance of our device.
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23. The finite element simulation is conducted by using commercial software COMSOL Multiphysics, http://www.comsol.com/ and AC/DC model has been chosen to simulate the static magnetic field, , External feld boundary condition has been used to mimic a unifor-m background static magnetic field from the outside of the, domain imposed onto the designed device. For the mesh size, we have used more than 10000 elements per square meter in, each case of our simulations.