Subject: (Lundquist) Why the focus on magnetic fields (fwd) Date: Tue, 5 Jan 1999 114158 -0600 (CST) From: "Roy L. Beavers" <rbeavers@llion.org> To: emfguru <rbeavers@llion.org> -------------------------------------------------- ---------- Forwarded message ---------- Date: Mon, 04 Jan 1999 21:39:05 From: marjlundquist@usa.net To: rbeavers@llion.org Cc: jeff.gordon@wellnow.com Subject: Why the focus on magnetic fields Roy, perhaps it is time to remind everyone that there is a sound scientific reason why there is an emphasis on magnetic fields (to the exclusion of electric fields) when the bioeffects of time-varying harmonic (that is, sinusoidal) electromagnetic fields are under study. Mammalian cells, like those of most living creatures, contain electrolytes (aqueous salt solutions). These are electrically conductive, and also provide mobile ions, which can move under the influence of an external electric field so as to electrically shield the cell from the external electric field. There is no analagous way for cells to shield themselves from external magnetic fields, so these penetrate living tissues quite freely. Harmonic magnetic fields by induction create harmonic electric fields everywhere that they are present. Since they can be present inside cells, they can produce electric fields there. These electric fields are different from any external electric field; they depend only on the characteristics of the magnetic field inside the cell. If an electric field is going to have a direct effect on the contents of the cell, then it will be this "generated inside the cell" electric field that does so. The external electric field is not unimportant. Because it can have an indirect effect on human health in certain circumstances (e.g., on people living near electric power lines) information regarding it in an experiment or field study should be documented, rather than ignored. However, the focus of attention has been on magnetic fields for good reason. As a variable to be manipulated in an experiment, the magnetic field is normally far more rewarding to the scientist. This doesn't mean that experiments should not be done that vary the external electric field from, say, a power line; it simply means that most bioeffects scientists are not going to be much interested in doing such a study, because varying the magnetic field is more fun for the scientist to do. Of course, such a study could be valuable from a public health perspective. I should remind everyone that only at very low frequencies (such as the power frequencies of 50 and 60 Hz) can one legitimately treat the electric and magnetic fields that exist in the space around a wire carrying electric current as separate, independent entities. At radio and higher frequencies, the entity that exists is an electromagnetic field, with the two fields strongly coupled inductively; if this field penetrates living tissue, there are BOTH electric and magnetic fields present, which are similar to the external electromagnetic field. I just want to remind everyone that there are other pressures besides the profit motive that determine priorities for research. -- Marjorie ********************************* Marjorie Lundquist, Ph.D., C.I.H. Bioelectromagnetic Hygienist P. O. Box 11831 Milwaukee, WI 53211-0831 USA ********************************* ____________________________________________________________________ Get free e-mail and a permanent address at http://www.netaddress.com/?N=1 Archive provided courtesy of WaveGuide, http://www.wave-guide.org Reprinted with permission of Roy Beavers, http://www.feb.se/EMF-L/EMF-L.html