The Physics
Factbook
An encyclopedia of scientific essays

Electric Current through the Atmosphere

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Bibliographic Entry Result
(w/surrounding text)
Standardized
Result
Gish, O. H. Air-Earth Conduction Current. Compendium of Meteorology, 1951: 113. "The conduction current is the largest portion of the air-earth current, far outweighing the contributions made by the precipitation current and convection current, which are zero in storm-free regions. Its magnitude is approximately 3 × 10-12 amperes (A) m-2, or about 1800 for the entire earth." 1800 A
Adams, Charles K. Nature's Electricity. Blue Ridge Summit: TAB Books, 1987: 119. "The rate of flow has been calculated to be between 1,400 and 1,800 amperes." 1400 -1800 A
Harrison, R.G., The Global Atmospheric Electrical Circuit & Climate [pdf]. 1980: 11. Typical parameters of the fair weather atmospheric electric circuit
Surface Potential Gradient (PG) E 120 V.mE-1
Conduction Current Density Jz 3 pA.m E-2
Air conductivity σ 20 fS.m E-1
Ionospheric potential Vi 250 kV
Total resistance of the atmosphere Rt 230 Ω
Total Air- Earth Current A 1800 A
Columnar resistance Rc 120 Pm
1800 A
Tapio, Juhani Tuomi, Ph.D. Fair-weather Atmospheric Electricity. 6 July 2001. "The number of simultaneously active thunder cells ("thunderstorms") over the globe is about 1000-2000, so the whole circuit carries a current of about 1000 amperes." 1000 A
Saviour, Engineer. Does a non linear electric field gradient generate gravity? Blaze Labs, 21 July 2005. "Its magnitude is approximately 3.5E-12 amp/m2, quite a feeble current density, which however for an earth mean radius of 6371.3 km, works out to be about 1800!! amperes for the entire earth." 1800 A

Have you ever witnessed an unusual incidence where an unplugged electrical appliance turned on? Or have you seen sparks come off ungrounded metal wires? The reason for these strange event may lie within the atmosphere. Yes, you heard correctly -- the atmosphere! It is the largest source of naturally produced electricity on earth. Several generators of this electricity are cosmic rays, thunderstorms, lightning and static electricity. The most interesting of these are thunderstorms and lightning. The earth can be considered as a big battery, and thunderstorms pump back electrons that the earth gives off. It is estimated that without that replenishment of electrons, the earth would lose all of its charge within an hour.

There are about 2,000 to 6,000 thunderstorms any given moment, which means about 100 lightning bolts per second. This translates to about 300,000 to 400,000 V between the earth and the ionosphere (the part of the atmosphere that can be ionized). Electron flow does not cease to exist in fair weather conditions between the earth and atmosphere. Fair weather condition is defined as any time when it is not rainy or stormy. The amount of electricity within the atmosphere at that time has been calculated to be between 1000 and 1800 A, with 1800 A being the most commonly accepted value.

The fair weather current flow occurs as follows: positive ions flow to the earth and negative ions flow to the ionosphere. Thus, positive charges deposit on Earth and negative charges deposit in the ionosphere. This flow depletes the extra electrons on Earth and the difference of charge allows the flow to cycle. Now you may ask why we all aren't being electrocuted while on Earth' surface. This is because the current is spread out over the whole of the earth; we won't feel it because it is distributed over a large area. This means about 3.5 microamps per square kilometer (9 microamps per square mile) or about 260 V between the feet and the head of a 1.8 meter tall (6 foot) person.

Terry Mathew -- 2006