Draft:Original research/Natural electric field of the Earth

The natural electric field of the Earth refers to the planet Earth having a natural direct current (DC) electric field or potential gradient from the ground upwards to the ionosphere. The static fair-weather electric field in the atmosphere is ~150 volts per meter (V/m) near the Earth's surface, but it drops exponentially with height to under 1 V/m at 30 km altitude, as the conductivity of the atmosphere increases.

"In this image [on the right], late afternoon sunlight casts long shadows from thunderhead anvils down onto southern Borneo. Near the horizon (image top center), more than 1000 kilometers away from the space station, storm formation is assisted by air currents rising over the central mountains of Borneo."

"Winds usually blow in different directions at different altitudes. At the time of this photo, high-altitude winds were clearly sweeping the tops off the many tallest thunderclouds, generating long anvils of diffuse cirrus plumes that trail south. At lower levels of the atmosphere, “streets” of white dots—fair-weather cumulus clouds—are aligned with west-moving winds. Small smoke plumes from forest fires in Borneo are also aligned west."

Natural electric field
The surface of the Earth is negatively charged, carrying 500,000 Coulombs (C) of electric charge (500 kC), and is at 300,000 volts (V), 300 kV, relative to the positively charged ionosphere. There is a constant flow of electricity, at around 1350 amperes (A) [approximately 1100 A], and resistance of the Earth's atmosphere is around 220 Ohms.[3] This gives a power of around 400 megawatts (MW). There are several theoretical proposals to harvest this power that Nikola Tesla elaborated (around 1901) and his followers. The main principle is to mimic the conditions when charged particles from space interact with the higher and lower layers of Earth's atmosphere. In any case averages a mere 0.8 microwatts per square metre of the earth's surface (compare solar radiation which is one billion times as large).

The charge is maintained by the stream of charged particles from the Sun. This process affects the ionosphere, as well as the troposphere, possibly causing thunderstorms. The electrical energy stored in the Earth's atmosphere is around 150 gigajoules (GJ).

The Earth-ionosphere system acts as a giant capacitor, of capacity 1.8 Farads.

The Earth's surface carries around -1 nC of electric charge per square meter.

Electrospheres
The "electrosphere [of the Earth is] at about 60 km of altitude".

Def. a "restricted region of the magnetosphere actually occupied by plasma" is called an electrosphere.

For an aligned rotator, "Rotation induces a large pole-to-equator potential difference [...] If the work function at the surface were huge, a surface charge would appear on the sphere, in order to keep E·B = 0 in the interior. [...] charged rings [...] are released from the surface, one at a time. If [a Jupiter] choice of rotation vs field is made [...], negative particles come from the poles, positive from the equatorial zone. Each ring has the same charge. A ring released follows the magnetic field lines until it reaches a local E·B = 0 point. Positive rings from the equatorial region are therefore trapped and fill up an equatorial torus. Negative rings from the pole fly up along the field lines but do not escape if the total system charge is positive. After each new ring is released, the positions of all the others are shifted to new E·B = 0 points. Ultimately one reaches the point where there is not enough surface charge left to scrape together to make another ring of either charge [...] leaving behind a dome of negative charge and a torus of positive charge." These restricted regions are the electrosphere.

Atmospheres
Below "approximately 50 km, conductivity [in the atmosphere] is mainly due to the presence of ions created by both cosmic rays and the Earth’s natural radioactivity."

"Above 60 km, however, free electrons are the main contributors to this conductivity."

"At surface level, the Earth’s natural radioactivity and cosmic rays play an equal role in creating these ions; at altitudes above 1 km, however, cosmic rays are mainly responsible for ion production in the Earth’s atmosphere."

"The electrical conductivity of the air at sea level is about 10−14 Siemens/m (1 Siemens = 1/ohm) and increases rapidly with altitude; at 35 km, where the air density is only 1% of that at the surface, conductivity is about 10−11 S/m. About approximately 80 km, however, the conductivity of the atmosphere becomes anisotropic due to the influence of the Earth’s magnetic field and the diurnal variations of the solar photoionization processes."

"The magnitude of [the natural electric] field decreases with altitude; at 10 km it has a value of about 3% of that at the surface, whereas at 30 km it is about 300 mV/m and 1 μV/m at about 85 km (Rakov and Uman, 2003)."

The "value of the electrical field intensity, 3×106 V/m, [is] for electrical breakdown between two parallel plane electrodes at sea level in dry air (Rakov and Uman, 2003)."

"The atmosphere [of the Earth] is a good conductor to slowly varying signals at about 50 km, a level known as the electrosphere. ... The voltage between the Earth and the electrosphere in regions of fair weather is about 300,000 V. To maintain this voltage the earth has about 106 C of negative charge on its surface, an equal positive charge being distributed throughout the atmosphere. In regions of fine weather, atmospheric currents of the order of 1000 A are continuously depleting this charge. Charge is apparently replaced by the action of thunderstorms including lightning. The thunderstorm system acts as a type of battery to keep the fine weather system charged."

"The surface-electrosphere potential difference VI causes an ionic leakage current to flow vertically. Currents of order 2000 A flow in the global circuit. Applying Ohm's law with VI ∼ 300 kV, gives a global atmospheric electrical resistance RT = 230 Ω. Variations in RT arise from changes in ion concentrations: RT has its principal contribution from the planetary boundary layer, because of ion removal by aerosol. The concentric sphere system formed by the electrosphere and the planet has a finite capacitance C, with a time constant RTC of ∼10 min [Chalmers, 1967]. The continued existence of an atmospheric electric field indicates that charge generation processes are continuously active."

Eclipses and occultations
An eclipse is when the light of the Sun or Moon is blocked such as the annular eclipse shown in the image at right on October 3, 2005, observed at Medina del Campo, Valladolid, España.

Observing a solar eclipse tells you that when both objects (the Sun and the Moon) are in the sky at the same time, close to each other, the Moon is between you and the Sun.

On April 25, 1838, an occultation of Mercury by the Moon occurred when Mercury was visible to the unaided eye after sunset. An occultation of Venus by the Moon occurred "on the afternoon of October 14", 1874. An earlier such occultation "occurred on May 23, 1587, and is thus recorded by [Tycho Brahe] in his Historia Celestis".

"Another Irish archaeoastronomer, Paul Griffin, says he has discovered confirmation of the world's oldest solar eclipse recorded in stone at Loughcrew.102 This eclipse, according to Griffin, happened in the late afternoon on 30 November 3340 BC.103 Depictions of the eclipse are found on petroglyphs in two chambers on the back stone of cairn T on Carnbane East and on stones 19 and 20 at Cairn L, another site which has a chamber structure aligned on the November/February cross-quarter days (sunrise) and probably aligned also on minor standstill moonrise.104"

Measurements "of the potential gradient of the electric field of the [Earth's] atmosphere during the annular eclipse of the sun, on 29 April 1976, on the island of Santorini [...] showed a diminution."

Fair weather
"This astronaut photograph [on the right], taken on February 26, 2003, is centered on the Kingdom of Denmark. The entire region is overlain with deposits of Pleistocene glaciers."

"Taking advantage of remarkably fair weather over north central Europe for the time of year, the crew of the International Space Station took this panoramic view that extends from the North Sea coast of the Netherlands on the left to the Baltic Sea shores of Sweden on the right. The late-winter landscape has little snow cover except over northeastern Germany, Sweden, and the rugged mountains of Norway. Such images, composed by astronauts, provide unique, synoptic perspectives of the Earth's geography and natural processes."

"Because of the Earth’s weak conducting capacity, a fair-weather current of about 2 × 10−12 A exists between the shells of this capacitor."

"In fair weather conditions, the surface of the Earth is negatively charged and the electric field in the atmosphere varies typically between 100 and 150 V/m."

"The Amazonian forest of about 5 x 106 km2, could, temporarily, conduct upward roughly 4 x 104 A, in the extreme – and admittedly somewhat unrealistic – case of all the transient signals being simultaneous on all the trees."

"It is known that the earth is negatively charged and that there is a difference of potential between the earth's surface and a layer of the upper atmosphere of the order of 3 x 105 volts in fine weather; therefore any body rising from the earth's surface to this upper layer of the atmosphere will carry a negative charge at a potential of approximately 3 x 105 volts to the surrounding air, assuming of course that it has lost no charge by dissipation."

"The electric field at the ground is an easily measurable quantity that has been measured at various locations. During fair weather the variation is small and the strength is ~ 100 V/m. However, the electric field on the ground can vary from -200 to 400 V/m if fog and haze ... In fair weather the ground electric field variations are due to changes in columnar resistance, ionospheric potential, and local conductivity".

Thunderstorms
A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are sometimes called thundershowers.

Thunderstorms can form and develop in any geographic location but most frequently within the mid-latitude, where warm, moist air from tropical latitudes collides with cooler air from polar latitudes.

Warm air has a lower density than cool air, so warmer air rises upwards and cooler air will settle at the bottom (this effect can be seen with a hot air balloon). Clouds form as relatively warmer air, carrying moisture, rises within cooler air. The moist air rises, and, as it does so, it cools and some of the water vapor in that rising air condenses. When the moisture condenses, it releases energy known as latent heat of condensation, which allows the rising packet of air to cool less than the cooler surrounding air continuing the cloud's ascension. If enough instability is present in the atmosphere, this process will continue long enough for cumulonimbus clouds to form and produce lightning and thunder. Meteorological indices such as convective available potential energy (CAPE) and the lifted index can be used to assist in determining potential upward vertical development of clouds. Generally, thunderstorms require three conditions to form:
 * 1) Moisture
 * 2) An unstable airmass
 * 3) A lifting force (heat)

All thunderstorms, regardless of type, go through three stages: the developing stage, the mature stage, and the dissipation stage. The average thunderstorm has a 24 km diameter. Depending on the conditions present in the atmosphere, each of these three stages take an average of 30 minutes.

A "thunderstorm supplies a negative charge to the Earth. The net positive space charge in the air between the ground and a height of ~ 10 km is nearly equal to the negative charge on the Earth's surface".

'Giant' "thunderclouds can produce transverse electric fields of tens of microvolts per meter in the equatorial plane of the midlatitude magnetosphere."

The "contribution to global thunderstorm activity by oceanic thunderstorms should be regarded as itself having a diurnal variation of some 18% in amplitude."

Concentric spherical capacitors
"The lower boundary of [the concentric spherical capacitor in theory] is the Earth's surface and the upper boundary is the electrosphere, a highly conducting layer at ~ 50 to 70 km. The electrosphere is defined as the height at which the equipotential condition is reached."

"In this model, the thunderstorm activity is the major charge generation mechanism while the fair weather conduction current is the basic consumer."

The capacitor stores 106 C.

Capacitor leakages
"Although there are many forms of charging associated with clouds, the charges must be separated faster than an 18-sec discharge rate (the capacitor leakage time-constant), otherwise the potentials will be nullified in the fair weather field."

Voltage gradients
"The voltage gradient is caused by the large potential difference between the lowest layer of the ionosphere, the electrosphere, and the surface. The resulting surface potential gradient in fair weather is ∼150 V m−1 but can be as high as about 105 V m−1 in thunderstorms before a lightning discharge [Krider and Roble, 1986]."

Large-scale "ionospheric and magnetospheric convection electric fields can be seen with little attenuation in the stratosphere. ... the effects of thunderstorms extend well into the ionosphere."

An "increase in the fair weather potential gradient ... occurs at about sunrise."

An "increase in the electrosphere potential could be the source of the sunrise effect. A mechanism ... which would account for the increase in electrosphere potential [identifies] the electrosphere with a specific part of the ionosphere."

Orography
Def. "the scientific study, or a physical description of mountains" is called orography.

The "Earth's orography [has an effect] on the electric potential distribution".

The orography affects "the potential surface in the troposphere and ionosphere".

Clouds
Clouds "act as electric insulators; space charge develops on the surface of the cloud and the distribution of fair-weather currents and fields in the vicinity of the cloud are altered."

The "electrical environment around clouds is such that high space charge densities can exist."

Charge centers
The "negative charge center is located where the temperature is about -10°C, while the positive charge is less restricted to temperature and can extend over large areas."

Currents
The "total current flowing upward from thunderstorms range from ~0.1 to 7.7 A with an average of ~1.4 A per thunderstorm cell."

The total global fair weather current is estimated to be ~1000 A (~750 A over oceans and ~250 A over continents).

The total global foul weather current is estimated from "the total number of active thunderstorms [and ranges] from 1500 to 2000 ... If these numbers are multiplied by the average output current (0.5 to 1.5 A), the total current ranges from 750 to 3000 A, which agrees somewhat with the [fair weather] estimate".

Conductivity
"Galactic cosmic rays are the main source of ionization that maintains the electrical conductivity of the atmosphere from the ground to ~70 km."

"Near the ground there is additional ionization due to the release of radioactive gases from the soil, and above ~ 60 km solar ultraviolet radiation becomes important."

"The number density of both positive and negative ions stays approximately constant between 20 and 60 km altitude. The negative ion density decreases rapidly above 60 km while the electron density increases. Above ~ 65 km the electron density is greater than the negative ion density".

South Pole
"Atmospheric electric field variations recorded under fair-weather conditions on the South Polar ice-shelf in summer show the site to be globally representative and therefore of possible use in monitoring variations in the electrosphere potential."