Space Electricit-An Innovation in Power Generation

7/29/2019 Space Electricit-An Innovation in Power Generation

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A technical paper presentation

On

Space Electricity

An Innovation in Electric Power Generation

Presented by:

M.NARENDRA KUMAR

N.SREENU,

Department of EEEDepartment of EEE

EMAIL ID: [email protected] EmailId:- [email protected]

Mobile.NO:-9160754569Mobile.No:-9640850009

Department of Electrical & Electronics Engineering


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CHEBROLU ENGINEERING COLLEGE

Chebrolu, Guntur(Dt).


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Abstract

Owing to the somewhat explosivedevelopment of the science of space

electricity during the past decade this article

covers a broad field of activity. The article

begins with a description and discussion of

the work that has been performed to

understand the electrical properties of the

basic materials involved in generating

processes in the atmosphere. The aspects

covered in this paper are the fair-weather

conditions, cluster ions concept, spherical

capacitor theory, and the major applications

of space electricity. Even the Fundamental

problem of space electricity and its solution

have been dealt with. The sections covered

also include the electrification of the upper

atmosphere and space, and a consideration

of the global electrical circuit and its related

electrical `balance sheet'. IndexTerms Air

Ion ,photoionization ,Thermodynamic.

What is Space Electricity?

Space 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. It was only after the

discovery of the electricity in the early

1700s that the electrical nature of the earths

atmosphere begun to be revealed. In 1708,

William Wall, watching the spark of a

discharge from a charged piece of amber,

observed that it similar to lightning. Around

the middle of the century, after the discovery

of the first electrical properties of matter, it


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became evident that lightning should be a

form of electricity associated in some way

with thunderstorms. Space electricity is the

regular diurnal(daily) variations of the

Earth's space electromagnetic network.

Its the study of electric charges and currents

in the atmosphere. Fossils suggest that the

terrestrial atmosphere has had lighting in it

for at least 250 million years.

Intro:

Benjamin Franklin was the first to design an

experiment to prove the electrical nature of

lightning. In July 1750, Franklin proposed

that electricity could be drawn from a cloud

by a tall metal pole. If the pole was insulated

from ground, and an observer brought a

grounded wire held by an insulating wax

handle near the pole, then a spark would

jump from the pole to the wire when an

electrified cloud was nearby. If this was the

case, it would be proved that the clouds

were electrically charged and, consequently,

that lightning was also an electrical

phenomenon. In June 1752, Franklin

conducted another experiment with the same

proposal, his famous experiment using a

kite. Instead of use a metal pole he used a

kite, since it could reach a greater elevation

than the pole and could be flown anywhere.

One more time sparks jumped from a key

tied to the bottom of the kite string to his

hands. This proved that lightning was also

an electrical phenomenon.

Fair Weather Condition:

negative when thunderstorms were nearby.

L. G. Lemonnier discovered that even when

there are no clouds,

the so-called fair weather condition, a

weak electrification exists in the

atmosphere. He also found some evidence

that the electrification varied from night to

day. In 1775, G. Beccaria confirmed the

existence of a diurnal variation in the fair

weather electrification and determined that

the polarity of the charge in the atmosphere

in fair weather condition was positive and

that it reversed to

Space layers:

Relationship of the atmosphere and

ionosphere The conductivity of the

atmosphere increases exponentially with


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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 space 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 presence of the earths

surface influences the concentration of ions,

aerosols and radioactive particles, through

its control over the wind, temperature and

water vapor distributions. Such influence is

dominated by the effects of turbulence. The

layer in which this influence is felt is called

the planetary boundary layer orexchange

layer. The depth of this layer is highly

variable, ranging from tens of meters to 3km

above the ground.

AIR-ION CONCEPT

A ion counter working on the principle onGerdiens condenser and plate antenna (as

shown in the figure) were used for ion

measurements ans airearth current densityrespectively. Variations in small and large

positive ion concentrations are almost

similar to each other. On the other hand,

variations in intermediate positive ion

concentrations are independent of variations

in the small/large positive ions and exhibit a

diurnal variation which is similar to that in

space temperature on fair weather days with

a maximum during the day and minimum

during the night hours. No such diurnal

variation in intermediate positive ion

concentration is observed on cloudy days

when variations in them are also similar to

those in small/large positive ion

concentrations. Scavenging of ions by

snowfall and trapping of rays from the


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ground radioactivity by a thin layer of snow

on ground, is demonstrated from

observations.

Variations in intermediatepositive ion

concentration are explained on the basis of

the formation of new particles by the

photolytic nucleation process. The number

concentration and size distribution ofaerosol particles in the size ranges 4.4163nm and 0.5 20 m diameters were also

measured simultaneously along with the

measurements of ion concentrations and the

airearth current density during blizard. Ionconcentrations of all categories and the air

earth current simultaneously decrease by

approximately an order of magnitude as the

wind speed increases from 5 to 10 ms1. The

rate of decrease is the highest for large ions,

lowest for small ions and in between the two

for intermediate ions.

Total aerosol number concentration

decreases in the 4.4 163 nm sizerange

but increases in 0.5 20 m size range with

wind speed. Size distribution of the

nanometer particles show a dominant

maximum at ~ 30 nm diameter throughout

the period of observations and the height of

the maximum decreases with wind speed.

However, larger particles show a maximum

at ~ 0.7 mTI

VIT

Cluster ions Concept:

The lower and middle atmosphere is weak

conductors due to the presence of trace

concentrations of ions. Ions are created by

ionization of the neutral molecules of air,

generally nitrogen and oxygen, by primary

and secondary cosmic rays, and by particles

and radiation produced by decay of

radioactive substances in the soil, like


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uranium and thorium, and in the air, like the

gas radon. As a result of the ionization of the

molecules, free electrons and positive ions,

in general singly charged, are created. The

electrons are, then, quickly attached to other

neutral molecules to produce negative ions.

The production of ions by cosmic rays

varies with altitude and latitude. The

production of ions due to the decay of

radioactive substances depends on the soil

characteristics. In particular, in the oceans it

is several orders of magnitude smaller than

in the continents. In general, the average

ionization (ion-pair production) rate over

the continent due to radioactive substances

is predominant on that due to cosmic rays

below 1 km. Above 1 km, the ionization rate

is dominated by the cosmic ray source. The

ionization rate is also sensitive to

meteorological conditions, and geomagnetic

and solar activity. Occasionally, the

ionization created by energetic particles

during times of high geomagnetic and solar

activity can dominate that produced by

cosmic rays above 20 km. Also, the 11-year

solar sunspot cycle produces a variation in

the ionization rate in the atmosphere. The

variation becomes more pronounced with

increasing height or geomagnetic latitude.

After the ions are formed, they react with

neutral molecules and attach to water

molecules from the water vapor always

present in the atmosphere, forming cluster

ions. These cluster ions are relatively stable,

and constitute most of the ions of molecular

size, also called small ions. Examples of

such ions are H3O+ (H2O) and O2-(H2O)n.

When small ions attach to aerosol particles,

they form large ions. During steady state

conditions, the concentration of small ions

in a given time and place is a radiation

ionization Cosmic and radioactive radiation

ionize air, and equal

numbers of molecular-size positive and

negative

small ions are formed; air becomes (weakly)

electrically conductive.

Small ions are also attached to airborne dust

(aerosol),

which thus regularizes the number of small

ions.

By collision ionization

Lightning and other result of the balance

between the production (ionization rate) and

destruction of ions. Small ions are destroyed

by recombination between them and by

attachment to large ions and aerosol

particles. The total average concentration of

small ions over the continents as over the

oceans is roughly the same and of the order

of 1000 cm-3, even though the ionization

rate is smaller over the oceans due to the


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absence of radioactive elements. This fact,

however, is compensated by the smaller loss

rate due to the lower aerosol concentration.

There are more positive small ions than

negative ones, and the difference produces a

net positive charge in the atmosphere. The

existence of a net positive charge near the

earths surface implies that additional

processes of ion production should exist,

since the ionization process produces equal

concentrations of negative and positive ions.

Charge Separation:

Space electricity involves phenomena which

are connected with the separation of electric

charges in the sub-ionospheric atmosphere

(below about 100 km height). In the

ionosphere and magnetosphere there occur

strong electric currents originating directly

from the solar-terrestrial interaction; in the

lower atmosphere, there flows a much

weaker electric current in the so-called

global circuit, which is maintained by the

thunderstorm activity. Charge separation

takes place in three ways:

Thermodynamically In a thundercloud,

small ice crystals collide with rime-growing

graupels; the crystals gain positive charge,

the graupels negative (the microscopic

mechanism is not yet well known).

Convection in the thundercloud carries the

ice crystals to the cloud top, the heavier

graupels staying in the mid-cloud: a

macroscopic dipole structure forms. By

discharges in the thundercloud ionize air

temporarily into electrically conducting

channels.

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


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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.

Photoionization:

Photo ionization is the physical process in

which an incident photon ejects one or more

electrons from an atom, ion or molecule.

The ejected electrons, known as

photoelectrons, carry information about their

pre-ionized states. For example, a single

electron can have a kinetic energy equal to

the energy of the incident photon minus the

electron binding energy of the state it left.

Photons with energies less than the electron

binding energy may be absorbed or scattered

but will not photoionise the atom or ion.

Fair-weather space electricity:

Fair weather electricity deals with the

electric field and the electrical current in the

atmosphere, and the conductivity of the air.

The discovery of the fair weather circuit

followed Ben Franklin's demonstration that

lightning is caused by electricity. Later

experimenters showed that clear, calm air

carries an electrical current which, it turns

out is the return path for the electrical

display we know as lightning. Space

electricity is like a massive photographic

flash. An electrical charge is built up, a

switch is closed, and electrons barge across

a gas, ionizing it and producing light. But a

flash is a complete circuit. In the case of the

Earth, the atmosphere completes the circuit

The thundercloud charge centres,

accumulating tens of coulombs of

electricity, are discharged mainly by

lightning:

cloud flashes (most abundant) cause mutual

neutralization of the centers; the lower

centre is also discharged to the ground by

negative ground flashes - and charges up the

earth(the


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positive centre is discharged similarly, but

by a smaller amount). An excess charge will

be left in the upper positive centre, and it

leaks by conduction to the surrounding air,

about one ampere per thunderstorm cell.

Because of the exponentially increasing

conductivity, most of this leak current is

guided to the ionosphere, where it is

distributed over the globe and charges the

upper atmosphere to a potential of about 300

kV with respect to the ground. This

"ionospheric potential" maintains the so-called fair-weather current, whose density is

about 2 pA/m2 (Pico amperes per square

meter). According to Ohm's law, the fair-

weather current density and the electric

conductivity are associated with a

downward electric field, about 100 V/m near

the ground. 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.

Why does not the (fair-weather) space

electric field cause a shock of 200 V to a

standing human? Because the human is

grounded in practice; the poorly conducting

air cannot charge up a grounded object.

Below a thundercloud, where the

groundlevel electric field may be tens of

kV/m, the situation is different - but then the

threat comes from a lightning strike.

Carnegie Curve:

The fair weather electric field presents

diurnal and seasonal variations. The typical

diurnal variation of the fair weather electric

field as a function of universal time was first

clearly identified by the measurements on

the research vessel Carnegie in the 1920s.

The so-called Carnegie curve is a result of

hourly values of the electric field averaged

over many days. The Carnegie curve is very

difficult to reproduce at land stations due to

local processes such as convection currents

and aerosol variations. In general,


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fluctuations in space charge density

associated with these processes within the

planetary boundary layer have an effect on

electric field roughly comparable in

magnitude to that of the Carnegie curve. If

local variations at land stations are removed

by averaging processes, the electric field on

the ground indeed shows a universal time

dependence similar to that of the Carnegie

curve. The fair weather electric field also

shows a seasonal variation. Even though the

overall pattern appears much the same of the

universal time variation, there are small

seasonal differences in the hour of

maximum field intensity, indicating changes

in the longitude of maximum thunderstorm

activity. Also, the average field shows

seasonal variations with maximum values in

the spring and summer in the Northern

Hemisphere, reflecting the fact that there is

more thunderstorms in these seasons in the

Northern Hemisphere than in the same

seasons in the Southern Hemisphere. This,

in turn, is a result of the fact that there is

more land in the Northern Hemisphere.

Fundamental problem of space

electricity:

In 1804, P. Erman, suggested for the first

time that the earth should be negatively

charged. In 1860, Lord Kelvin put forward

the argument that positive charges must

exist in the atmosphere to explain the

electrification in fair weather. In 1785, C. A.

Coulomb discovered that the air is

conductive, observing that a well insulated

conductor exposed to air gradually loses its

charge. It was then estimated that the earth

would lose almost all of its charge to the

conductive atmosphere in less than an hour

unless the supply were replenished. This

raised what has become known as the

fundamental problem of space electricity,

that is, how the earths negative charge is

maintained.

Solution:

The first attempt to solve this problem was

suggested by C. T. R. Wilson in 1920.

Wilson developed the hypothesis, known as

the spherical capacitor theory that the

earths surface and an equipotential layer at

some height must behave like plates of a

spherical capacitor. The equipotential layer

was firstly termed electrosphere and was

supposed to be somewhere between 40 and

60 km. Later, it was considered to be located

coincident with the ionosphere.

Applications:

A Lighting Harnessing Power Plant

This concept is perhaps not as impractical as

it once was. The main limiting factor of

implementing a lightning capturing scheme


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such as this was the inability to be

able to store large amounts of electricity for

later use. However, new Utility Scale

Battery technology or other energy storage

technologies such as Flywheels or

Capacitors could be used to store the

electricity captured from lightning in

massive quantities, for later grid use.

Obviously, a lightning capturing power plant

would only be practical in regions with

frequent thunderstorms, such as Florida.

Conclusion:

How hard would it be to build an array of

lighting rods to capture periodic

thunderstorm electricity? The biggest hurdle

would really be creating power plant

infrastructure that could survive the harsh

surges created by lightning strikes, but even

that seems possible with current technology

and materials. Electrical and building design

engineers could come up with an innovative

way to make it work. Specially designed

buffer/insulation and transformer materials

could be used to safely capture and harness

the massive amounts of electricity generated

during a lighting strike, and transfer it to

large storage device for later use.

References:

1.The Space Electricity Journal by Basil

Ferdinand

2.www.en.wikipedia.org

3.www.SpaceElectricity.org

4.NewsLetter on Space Electricity

Space Electricit-An Innovation in Power Generation

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