Biological Effects of Magnetic Fields

The biological effects of magnetic fields are classified into three categories: the effects of time-varying magnetic fields, the effects of static magnetic fields, and effects caused by compounding static magnetic fields with other energy forms such as light or radiation. In each category, a different approach is required in investigations of biomagnetic effects. Magnetic brain stimulation has been achieved with a resolution of 5 mm by eddy currents concentrated in the target, induced by a pair of opposing time-varying magnetic fields. No clear biological effects of static magnetic fields have been observed, except for a few special effects such as the magnetic orientation of fibrin. Static magnetic fields of up to 6.34 T do not affect the embryonic development of Xenopus laevis. An experiment has been performed which demonstrates the phenomenon of extinction of a candle flame by a magnetic field. A "magnetic curtain" model has been introduced to explain this phenomenon. Paramagnetic oxygen is indispensable to the formation of the magnetic curtain.