Three primary classes of experiments of electromagnetic influence (Fig­ure 1) can be distinguished viz.:

1. Predominantly magnetic fields: Near-field regime (Permanent, slowly changing, and pulsed fields from magnetic coils)

2. Predominantly electric fields: Near-field regime (Permanent or slowly changing)

3. Fields with both electric and magnetic components, with ratios be­tween 0.1 and 10: Far-field regime (typical EMF oscillation fre­quency is 100 kHz or more)

4. Fields from (I, II, or III) with unique spatial and/or temporal topol­ogy

Group I is represented relatively larger, mostly because of simplicity of experimental setup and extended penetration depth of magnetic field inside the water containing systems (Figure 4). The generated fields are either static magnetic fields or oscillating magnetic fields created by either permanent magnets or electromagnets, like Helmholtz and Solenoid coils. The biological experiments generally use a standard bipolar configuration with a N/S magnetic or +/- electric field for stimulation.

Group II is most often used in electroporation where strong pulsed electric fields (or PEF’s) are used for reversible membrane permeabiliza — tion to induce the uptake or release of some cell ingredients or foreign molecules. Group III is electromagnetic energy that propagates as a wave at higher frequencies and is considered as the far-field regime via an an­tenna, magnetron, or klystron. This classification encompasses non-ioniz­ing radiowaves and microwaves, as well as optical and ionizing radiations such as IR, visible, UV, X-ray and Gamma radiation.

The following section on the effects of electromagnetic fields has been organized by the type of the EM treatment and further categorized on the basis of growth and physiological processes that have been studied within each treatment group.