The
sun is the most powerful and easily accessible source of energy to
us. India's landmass gets about 300 clear, sunny days every year.
According to an estimate, India's theoretical solar power reception,
on only its land area, is about 5000 Petawatt-hours ( 10^15 watts x
hours) per year. The daily average solar energy incident over India
varies from 4 to 7 Kilo watt hours for every square meter of land
with about 1500–2000 sunshine hours per year.
But
how does sun produce all this energy? To understand this, we need to
go to basics of particle physics. All matter has mass, which means
that the mass is the basic quality of matter. scientific community
believes that the universe has been created by 12 types of basic
particles which include Quarks of 6 types, Electrons and some more
particles, which have a short, transitory life. There are also forces
that gather atomic and sub-atomic particles at designated places,
assemble them in required order and then hold them together
permanently. First of these forces is the Gravitational force, whose
power, we all know. The next force is the electromagnetic force,
which makes all electrical stuff that we use work and has a profound
effect on the daily life of modern humans. Going to sub-atomic level,
this force ensures that the nucleus and the electron stay together in
form of the atom, which happens to be the basic building block of all
the materials we use. The third or the strong nuclear force ensures
that atoms and electrons form various orders and arrangements and
stay in those arrangements in spite of disturbing effects of the
electromagnetic force and actually give us all the elements of the
periodic table.
There
is one more basic force known as Weak nuclear force. This works
essentially for the nuclear transformations that go on inside the
stars, which also includes our Sun. This force is principally
responsible for getting us the energy from the Sun or in reality, our
life. How does the Sun manage to perpetually create all this
uninterrupted energy? Sun is a perfect spherical ball of hot plasma,
the fourth state of matter. Plasma is a highly ionised gaseous state
of matter. A plasma can be created by heating a gas and subjecting it
to a strong electromagnetic field applied with a laser or microwave
generator. This decreases or increases the number of electrons,
creating positive or negative charged particles called ions, and is
accompanied by the dissociation of molecular bonds, if present. The
presence of a significant number of charge carriers makes plasma
electrically conductive so that it responds strongly to
electromagnetic fields. Like gas, plasma does not have a definite
shape or a definite volume unless enclosed in a container. Plasma
also is the most abundant form of ordinary matter in the Universe.
Plasma shows internal convective motion like a gas cloud and also
generates a magnetic field like a dynamo process.
The
energy is created inside the sun by a nuclear process known as fusion
in which hydrogen nuclei, bound together by strong gravitational
force, fuse in a chain of reactions to produce finally Helium. The
actual reaction takes place in three steps. In the first step two
protons (hydrogen nuclei) fuse to produce a deuterium ( a stable
isotope of Hydrogen, nucleus of which contains an additional neutron)
and a positron ( an electron like particle with a positive electrical
charge.) In the second step this deuterium atom fuses with another
hydrogen proton to produce a light isotope of Helium, He3. After
these two steps are repeated, resultant two atoms of He3, further
fuse to produce He4 atom and release 2 neutrons.
The
most basic problem with Plasma is that it is extremely difficult to
confine it in a Steady State so that it can function like the sun.
This can be done by confining it in a special Super Conducting vessel
known as Tokamak by passing Electric current with microwave
wavelengths through it. This keeps the plasma hot and confined inside
the Tokamak. A current of the order of 70,000 amperes is passed and
plasma is heated to 200 to 300 million degrees. In such process,
plasma gets confined inside and through that heat, energy can be
generated.
Institute
of Plasma Research( IPR), located on the outskirts of Indian city of
Ahmedabad, is an autonomous physics research institute. It is
involved in research in aspects of plasma science, including basic
plasma physics, research on magnetically confined hot plasmas and
plasma technologies for industrial applications. It has been running
experiments on hot plasma for last 25 years with the contribution
from nearly 50 scientists.
IPR
has been successful in producing and confining plasma inside the
Tokamak from Hydrogen gas with the help of superconducting magnets.
This is very similar to what happens inside the Sun and s similar to
creating sun-like energy inside a laboratory. This heat can be
extracted in the form of energy and can be connected to turbines to
generate electricity. The process is so energy efficient that about
5,000 MW of thermal energy can be produced by using just 50 MW of
electricity.
IPR's
successful experiments have brought in the realms of possibility,
generation of power, exactly in the same way the sun has been doing
it for us for Billions of years, even when we were not there.
22nd
April 2015
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