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7/29/2019 Space Electricit-An Innovation in Power Generation
1/12
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