Atmospheric electricity

From Wikipedia, the free encyclopedia

Cloud to ground Lightning in the global atmospheric electrical circuit. This is an example of plasma present at Earth's surface. Typically, lightning discharges 30,000 amperes, at up to 100 million volts, and emits light, radio waves, x-rays and even gamma rays ^[1]. Plasma temperatures in lightning can approach 28,000 kelvins and electron densities may exceed 10²⁴/m³.

Atmospheric electricity is the regular diurnal variations of the Earth's atmospheric electromagnetic network (or, more broadly, any planet's electrical system in its layer of gases). The Earth’s surface, the ionosphere, and the atmosphere is known as the global atmospheric electrical circuit. Atmospheric electricity is a multidisciplinary topic.

[edit] History

In 1708, Dr. William Wall was one of the first to observe that spark discharges resembled miniature lightning, after watching such an event from a charged piece of amber. In the middle of the 18th century, Benjamin Franklin's experiments showed that the electric phenomena of the atmosphere were not fundamentally different from those produced in the laboratory. In July of 1750, Franklin hypothesized that electricity could be taken from clouds via a tall metal aerial. With ground-insulated aerials, an experimenter could bring a grounded lead with an insulated wax handle close to the aerial, and observe a spark discharge from the aerial to the grounding wire. In May of 1752, Thomas Francois d'Alibard affirmed that Franklin's theory was correct.

Around June of 1752, Franklin reportedly performed his famous kite experiment. L. G. Lemonnier (1752) reproduced Franklin experiment with an aerial, but substituted the ground wire with some dust particles (testing attraction). He went on to document the fair weather condition, the clear-day electrification of the atmosphere, and the diurnal variation of the atmosphere's electricity. G. Beccaria (1775) confirmed Lemonnier's diurnal variation data and determined that the atmosphere's charge polarity was positive in fair weather. H. B. Saussure (1779) recorded data relating to a conductor's induced charge in the atmosphere. Saussure's instrument (which contained two small spheres suspended in parallel with two thin wires) was a precursor to the electrometer. Saussure found that the fair weather condition had an annual variation. Saussure found that there was a variation with height, as well. In 1785, C. A. Coulomb discovered the conductivity of air. His discovery was contrary to the prevailing thought at the time that the atmospheric gases were insulators (which they are to some extent, or at least not very good conductors when not ionized). His research was unfortunately completely ignored. P. Erman (1804) theorized that the Earth was negatively charged. J. C. A. Peltier (1842) tested and confirmed Erman's idea. Lord Kelvin (1860s) proposed that atmospheric positive charges explained the fair weather condition and, later, recognized the existence of atmospheric electric fields.

Over the course of the next century, using the ideas of Alessandro Volta and Francis Ronald, several researchers contributed to the growing body of knowledge about atmospheric electrical phenomena. With the invention of the portable electrometer and Lord Kelvin's 19th century water-dropping condenser, a greater level of precision was introduced into observational results. Towards the end of the 19th century came the discovery by W. Linss (1887) that even the most perfectly insulated conductors lose their charge, as Coulomb before him had found, and that this loss depended on atmospheric conditions. H. H. Hoffert (1888) identified individual lightning downward strokes using early camera and would report this in "Intermittent Lightning-Flashes". J. Elster and H. F. Geitel, who also worked on thermionic emission, proposed a theory to explain thunderstorm's electrical structure (1885) and, later, discovered atmospheric radioactivity (1899). By then it had become clear that freely charged positive and negative ions were always present in the atmosphere, and that radiant emanations could be collected. F. Pockels (1897) estimated lightning current intensity by analyzing lightning flashes in basalt and studying the left-over magnetic fields (basalt, being a ferromagnetic mineral, becomes magnetically polarised when exposed to a large external field such as those generated in a lightning strike).

Using a Peltier electrometer, Luigi Palmieri researched atmospheric electricity. Nikola Tesla and Hermann Plauson investigated the production of energy and power via atmospheric electricity. Tesla also proposed to use the atmospheric electrical circuit to transmit energy wirelessly over large distances (see his Wardenclyffe Tower and Magnifying Transmitter). The Polish Polar Station, Hornsund, has researched the magnitude of the earth's electric field and recording its vertical component. Discoveries about the electrification of the atmosphere via sensitive electrical instruments and ideas on how the Earth’s negative charge is maintained were developed mainly in the 20th century. Whilst a certain amount of observational work has been done in the branches of atmospheric electricity, the science has not developed to a considerable extent. It is thought that any apparatus which might be used to extract useful energy from atmospheric electricity would be prohibitively costly to build and maintain, which is probably why the field has not attracted much interest.

[edit] Description

Atmospheric electricity abounds in the environment; some traces of it are found less than four feet from the surface of the earth, but on attaining greater height it becomes more apparent.

[edit] Outer space and near space

Electric currents created in sunward ionosphere.

In outer space, the magnetopause flows along the boundary between the region around an astronomical object (called the "magnetosphere") and surrounding plasma, in which electric phenomena are dominated or organized by this magnetic field. Earth is surrounded by a magnetosphere, as are the magnetized planets Jupiter, Saturn, Uranus and Neptune. Mercury is magnetized, but too weakly to trap plasma. Mars has patchy surface magnetization. The magnetosphere is the location where the outward magnetic pressure of the Earth's magnetic field is counterbalanced by the solar wind, a plasma. Most of solar particles are deflected to either side of the magnetopause, much like water is deflected before the bow of a ship. However, some particles become trapped within the Earth's magnetic field and form radiation belts. The Van Allen radiation belt is a torus of energetic charged particles (i.e. a plasma) around Earth, trapped by Earth's magnetic field.

At elevations above the clouds, atmospheric electricity forms a continuous and distinct element (called the electrosphere) in which the Earth is surrounded. The electrosphere layer (tens of kilometers above the surface of the earth to the ionosphere) has a high electrical conductivity and is essentially at a constant electric potential. The ionosphere is the inner edge of the magnetosphere and is the part of the atmosphere that is ionized by solar radiation. Photoionisation is a physical process in which a photon is incident on an atom, ion or molecule, resulting in the ejection of one or more electrons. The ionosphere forms the inner edge of the magnetosphere.

[edit] Atmospheric layers

Relationship of the atmosphere and ionosphere

The conductivity of the atmosphere increases exponentially with altitude. The amplitudes of the electric and magnetic components depend on season, latitude, and height above the sea level. The greater the altitude the more atmospheric electricity abounds. The exosphere is the uppermost layer of the atmosphere and is estimated to be 500 km to 1000 km above the Earth's surface, and its upper boundary at about 10,000 km. The thermosphere (upper atmosphere) is the layer of the Earth's atmosphere directly above the mesosphere and directly below the exosphere. Within this layer, ultraviolet radiation causes ionization. The mesosphere (middle atmosphere) is the layer of the Earth's atmosphere that is directly above the stratosphere and directly below the thermosphere. The mesosphere is located about 50-80/85km above Earth's surface. The stratosphere (middle atmosphere) is a layer of Earth's atmosphere that is stratified in temperature and is situated between about 10 km and 50 km altitude above the surface at moderate latitudes, while at the poles it starts at about 8 km altitude. The stratosphere sits directly above the troposphere and directly below the mesosphere. The troposphere (lower atmosphere) is the densest layer of the atmosphere. The planetary boundary layer (PBL), also known as the atmospheric boundary layer (ABL), is the lowest part of the atmosphere and its behavior is directly influenced by its contact with the planetary surface. It is also known as the "exchange layer". There is a potential gradient at ground level and this corresponds to the negative charge in and near the Earth's surface. This negative potential gradient falls rapidly as altitude increases from the ground. Most of this potential gradient is in the first few kilometers. Conversely, the positive potential gradient rises rapidly as altitude increases from the ground.

[edit] Earth-Ionosphere cavity

Potential difference between the ionosphere and the Earth is maintained by thunderstorms' pumping action of lightning discharges. In the Earth-ionosphere cavity, the electric field and conduction current in the lower atmosphere are primarily controlled by ions. Ions are have the characteristic parameters such as mobility, lifetime, and generation rate that vary with altitude.

The Schumann resonance is a set of spectrum peaks in the ELF portion of the Earth's electromagnetic field spectrum. Schumann resonance is due to the space between the surface of the Earth and the conductive ionosphere acting as a waveguide. The limited dimensions of the earth cause this waveguide to act as a resonant cavity for electromagnetic waves. The cavity is naturally excited by energy from lightning strikes.

[edit] Patents

In the United States Patent Office classification, the main classification is 310/308 Electrical Generator or Motor / Charge accumulating. Other applicable classes regarding atmospheric electricity include:

• 307/149 Electrical Transmission or interconnection systems / Miscellaneous Systems
• 320/166 Electricity: Battery of Capacitor Charging or Discharging / Capacitor Charging or Discharging
• 361/212 Electricity: Electrical Systems and Devices / Discharging or Preventing accumulation of Electric Charge(e.g., Static Electricity)
• 174/6 Electricity: Conductors and Insulators / Earth Grounds
• 174/2 Electricity: Conductors and Insulators / Lightning Protection

Source: United States Patent Office classification system - Classification Definitions, June 30, 2000.

Patents related to atmospheric electricity

American

• Vion, U.S. Patent 28793, "Improved method of using atmospheric electricity", June 1860.
• Ward, U.S. Patent 126356, "Improvement in collecting electricity for telegraphing", using towers to collect atmospheric electricity, April 1872.
• Loomis, U.S. Patent 129971, "Improvement in telegraphing" "without the aid of wires or artificial batteries", Jul. 1872.
• Palencsar, U.S. Patent 674427, "Apparatus for collecting atmospheric electricity" using a balloon, May 1901.
• Pennock, U.S. Patent 911260, "Apparatus for collecting atmospheric electricity", using one or more balloons, Feb. 1909.
• Pennock, U.S. Patent 1014719, "Apparatus for collecting electrical energy", Jan. 1912.
• Plauson, U.S. Patent 1540998, "Conversion of atmospheric electric energy". Jun. 1925.
• Britten, U.S. Patent 1826727, "Radio apparatus" "to economize and conserve the current, and to regulate and clarify the tone", Oct. 31, 1931.
• Crump, U.S. Patent 2813242, "Powering electrical devices with energy attracted from the atmosphere" using transistor circuits, Nov. 12, 1957.
• Ruhnke, U.S. Patent 3273066, "Apparatus for detecting changes in the atmospheric electric field", Sep. 1966.
• Smith, U.S. Patent 3205381, "Ionospheric battery", March, 1962.
• Kasemir, U.S. Patent 3458805, "Electric field meter having a pair of rotating electrodes", Jul. 1969.
• Winn, et al., U.S. Patent 4025913, " Electrical field sensing and transmitting apparatus", May. 1977.
• Colombo, et al., U.S. Patent 4097010, " Satellite connected by means of a long (100 km) tether to a powered spacecraft", Jun. 1978.
• Carpenter, Jr., U.S. Patent 4180698, " System and equipment for atmospherics conditioning", Dec. 1979.
• Shoulders, U.S. Patent 5018180, " Energy conversion using high charge density", May 1991 .
• Shoulders, U.S. Patent 5123039, " Energy conversion using high charge density", Jun. 1992.
• Mims, U.S. Patent 5367245, " Assembly for the induction of lightning into a superconducting magnetic energy storage system", Nov. 1994.

Other

• Traun's Forschungs laboratorium, GB157263

[edit] See also

• Geophysics, Atmospheric sciences, and atmospheric physics
• Earth's magnetic field
• Sprites and lightning
• Whistler (radio)
• Telluric currents
• Charles Chree Medal
• Electrodynamic tethers
• relaxation time
• electrode effect
• Solar radiation

[edit] References and further readings

General references

• Transcript of hand-written article signed by Dr. Mahlon Loomis, January 7, 1872. (from Radio News, November, 1922, pages 974-978 (Loomis lecture extract))
• "Atmospheric electricity", dge.inpe.br.
• Chree, Charles, "Atmospheric electricity", Britannica Encyclopedia. Encyclopædia Britannica, 1926.

Citations

1. ^ See Flashes in the Sky: Earth's Gamma-Ray Bursts Triggered by Lightning

Journals

• Anderson, F. J., and G. D. Freier, "Interactions of the thunderstorm with a conducting atmosphere". J. Geophys. Res., 74, 5390-5396, 1969.
• Brook, M., "Thunderstorm electrification", Problems of Atmospheric and Space Electricity. S. C. Coroniti (Ed.), Elsevier, Amsterdam, pp. 280-283, 1965.
• Farrell, W. M., T. L. Aggson, E. B. Rodgers, and W. B. Hanson, "Observations of ionospheric electric fields above atmospheric weather systems", J. Geophys. Res., 99, 19475-19484, 1994.
• Fernsler, R. F., and H. L. Rowland, "Models of lightning-produced sprites and elves". J. Geophys. Res., 101, 29653-29662, 1996.
• Fraser-Smith, A. C., "ULF magnetic fields generated by electrical storms and their significance to geomagnetic pulsation generation". Geophys. Res. Lett., 20, 467-470, 1993.
• Krider, E. P., and R. J. Blakeslee, "The electric currents produced by thunderclouds". J. Electrostatics, 16, 369-378, 1985.
• Lazebnyy, B. V., A. P. Nikolayenko, V. A. Rafal'skiy, and A. V. Shvets, "Detection of transverse resonances of the Earth-ionosphere cavity in the average spectrum of VLF atmospherics". Geomagn. Aeron., 28, 281-282, 1988.
• Ogawa, T., "Fair-weather electricity". J. Geophys. Res., 90, 5951-5960, 1985.
• Sentman, D. D., "Schnmann resonance spectra in a two-scale-height Earth-ionosphere cavity". J. Geophys. Res., 101, 9479-9487, 1996.
• Wåhlin, L., "Elements of fair weather electricity". J. Geophys. Res., 99, 10767-10772, 1994.

Other readings

• Richard E. Orville (ed.), "Atmospheric and Space Electricity". ("Editor's Choice" virtual journal) -- "American Geophysical Union". (AGU) Washington, DC 20009-1277 USA
• Schonland, B. F. J., "Atmospheric Electricity". Methuen and Co., Ltd., London, 1932.
• Macgorman, Donald R., W. David Rust, D. R. Macgorman, and W. D. Rust, "The Electrical Nature of Storms". Oxford University Press, March 1998. ISBN 0-19-507337-1
• Cowling, Thomas Gilbert, "On Alfven's theory of magnetic storms and of the aurora", Terrestrial Magnetism and Atmospheric Electricity, 47, 209-214, 1942.
• H. H. Hoffert, "Intermittent Lightning-Flashes". Proc. Phys. Soc. London 10 No 1 (June 1888) 176-180.

[edit] External articles

• Orville, Dick, "Atmospheric Electricity-related terms". (American Meteorological Society, Glossary of Meteorology, Second Edition, 2000.)
• "International Commission on Atmospheric Electricity". Commission of the International Association Of Meteorology And Atmospheric Physics.
• "Lightning and Atmospheric Electricity". Global Hydrology and Climate Center, NASA.
• Kieft, Sandy, "The Langmuir Laboratory for Atmospheric Research". New Mexico Institute of Mining & Technology.
• "Chauncy J. Britten’s Atmospheric Electrical Generator", Rex Research.
• "Power from the Air". Science and invention (Formerly electrical experimenter), Feb. 1922, no. 10. Vol IX, Whole No. 106. New York. (nuenergy.org)
• "Power from the Air". Science and invention (Formerly electrical experimenter), March 1922. (nuenergy.org).
• "RF Energy via Ionosphere". RF Energy Concepts Sec. 101 Rev. Nov., 2003
• Peter Winkler, "Early observations of and knowledge on air electricity and magnetism at Hohenpeißenberg during the Palatina". German Weather Service, Meteorological Observatory. (PDF)
• "Atmospheric Electricity". Meridian International Research.