  Using the weak field approximation, we can express the theory of general
relativity in a Maxwell-type structure comparable to electromagnetism. We find
that every electromagnetic field is coupled to a gravitoelectric and
gravitomagnetic field. Acknowledging the fact that both fields originate from
the same source, the particle, we can express the magnetic and electric field
through their gravitational respective analogues using the proportionality
coefficient k. This coefficient depends on the ratio of mass and charge and the
ratio between the electromagnetic and gravitic-gravitomagnetic permittivity and
permeability respectively. Although the coefficient is very small, the fact
that electromagnetic fields in material media can be used to generate
gravitational and gravitomagnetic fields and vice versa is not commonly known.
We find that the coupling coefficient can be increased by massive ion currents,
electron and nuclear spin-alignment. Advances in material sciences, cryogenic
technology and high frequency electromagnetic fields in material media may lead
to applications of the derived relationships.
