Why arguments based on photon energy may be highly misleading for power line frequency electromagnetic fields.
When evaluating possible mechanisms by which low frequency electromagnetic fields may have a biological effect, arguments based on photon energy have often been used in a misleading way. For visible light the concept of photons has proved to be very useful in explaining experimental findings. However, the concept of photons cannot be used without major modifications in describing phenomena related to near field problems at power frequency (50 or 60 Hz) electric and magnetic fields. For this regime, the photon description is very complex. A very high number of highly coherent photons must be used in a quantum electrodynamic description of low frequency electromagnetic field phenomena. Thus, one-photon interaction descriptions must be replaced by multiple-photon interaction formalism. However, at low frequencies, a classical electromagnetic field description is far more useful than quantum electrodynamics. There is in principle no difference in how much energy an electron can pick up from a low frequency electric field as compared to from a high frequency photon. Thus, the total gain in energy is not limited to the energy carried by a single photon, which is E = hv, where h is Planck's constant and (v) is the frequency of the radiation. However, the time scale of the primary event in a mechanism of action is very different for ionizing radiation compared to power line frequency fields. The advice is to consider the time scale given by the inverse of the frequency of the fields, rather than photon energy, when one use physics as a guidance in evaluating possible mechanisms for biological effects from low frequency electromagnetic fields.
Department of Physics, University of Oslo, Oslo, Norway. a.i.vistnes@fys.uio.no
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D004560:Electricity; D004574:Electromagnetic Fields; D008027:Light; D017785:Photons; D011789:Quantum Theory; D011846:Radio Waves; D014466:Ultraviolet Rays; D014965:X-Rays