NUCLEAR FUSION: How much it takes to mimic a star ?

Reading Time: 10 minutes

The greatest stuff that matters more than anything else for humans is the source of energy to run his dear machines. In fact, he is far more hearty and concerned about food for his machines than himself. This hunger had led him to exploit coals, gas, petroleum and in some amount the nuclear and renewable sources to meet his ever-increasing needs. There is absolutely no doubt that the standard of living of each human on earth should be equal and magnificent, this comes on the cost of energy expenditure. The point of concern is that whatever ways he has devised has many issues associated with it, the limited amount and harmful effects on the environment are the most depressing. The coal mines and oil wells in the near future will definitely exhaust. Imagine where would we stand if we have no source of energy for our hungry electric motors, IC engines, etc. The production of energy in a conventional way is fast approaching to its ends along with it causing hostile climate changes, the scary nightmare for us.

Now just imagine the deployment of a source to meet the energy demand that tends to provide humans for thousands of years, in fact, millions of years of service and also has almost negligible effect on our environment, just imagine the peace and prosperity of humans on earth, there would be heaven, no wars, no one deprived.

And I am not just asking you to imagine instead believe it. This feat if humans establish than it would surely be his greatest achievement.

You have guessed it right the NUCLEAR FUSION, creating miniature stars on earth. Yes this seems impossible surely, we have been failing at it from tens of decades but this is the reason why human rules on earth because “he believes in believing and achieving”.NUCLEAR FUSION: How much it takes to mimic a star ?Basically, this blog intends to discuss the phenomenon of the nuclear furnace of the universe and endeavor required to mimic it on earth. We will discuss in somewhat detail the classical physics and the quantum physics behind the process, and what exactly we need to do to get the sun here on earth, the advantages and the work done and the reason for failure till now thereby quenching our thirst of curiosity regarding this topic.

THE PHYSICS OF NUCLEAR FUSION

Atoms are fundamental building blocks of matter, they comprise of a nucleus and the electrons orbiting around it. The nucleus, volume wise is very small, a grain in a room if compared but carries the 99.999% mass of the whole atom. The nucleus is made up of particles called hadrons the protons and neutrons. Refer to the standard model for particle classification.

Protons have unit positive electric charge and neutrons are neutral. Since the protons are very close thus electrostatic force must be repelling with huge magnitude, but we know nucleus do exist hence we can easily conclude that some stronger attracting force must be there to bind them together, the force should be enormous as well as very short range, otherwise there would be no discrete matter at all. These forces are named nuclear force and they are characteristics property of both protons and neutron.

So as result of work done by strong nuclear force against electrostatic repulsion, a large amount of energy is released when a nucleus is formed, this energy released from the formation of a nucleus is called binding energy. You can see that more the number of nucleons are there more the energy is released but this hold true only up to nucleus which contains less than 56 nucleons, as nuclear force gets weaker exponentially with increasing distance.

NUCLEAR FUSION: How much it takes to mimic a star ?

So we can analyze that to tap this enormous binding energy we have to synthesize nucleus, there are two techniques to make this happen:

  1. Either you make a naturally available bigger nucleus unstable by some process and forcing it to decay into daughter nuclei and hence releasing the corresponding binding energies of more stable daughters, this method is called the NUCLEAR FISSION, the concept behind current nuclear power plants.
  2. The other more difficult way is to force already highly stable smaller nuclei together to form an unstable nucleus which again decays into more stable nuclei and releasing significant binding energies, this method is called NUCLEAR FUSION, the concept behind future nuclear power plants.

The complication in the second case can easily be spotted. To make a bigger nucleus unstable is far easier than to force two smaller stable nuclei to form an unstable nucleus because nucleus greater than 56 atomic number are having less binding energy per nucleon hence firing it with a neutron or something can easily make it lose its stability. Whereas forcing two nuclei to fuse, is certainly a tedious job on earth at least. We have to overcome the great electrostatic force as they approach closer to form a new nucleus, but the unstable nucleus decay to products that will have much higher binding energy, as graph increases linearly till atomic number < 56.

WHAT QUANTUM SAYS?

Before I start this section let me make you one thing clear, strictly saying “NO ONE ON THIS EARTH IS ALLOWED TO ASK THE QUESTION WHY, WHEN PHYSICISTS ARE DESCRIBING HOW NATURE WORKS!!!”, we have to just follow through their theories because it is the way it is. We just have to check if their theories actually fit into the phenomenon or not, that is the aim.

Quantum description of nature is seriously very hard to understand and far harder to sing it to others. However weird and virtual quantum theory appears, it is the reason behind this technological era and also future “the quantum computers!”, won’t go off topic.

Quantum describe particle not as like definite point. Instead, it says that particles are mere disturbances in their corresponding field and describe them mathematically as wave function or probability functions. Classical mechanics strictly deny this process to occur as electrostatic force tends to infinity as distance tends to zero, but quantum says that it can happen, there is a probability. This is called the quantum tunneling effect.

Wikipedia says: “Quantum tunneling is the phenomenon where a particle passes through a potential barrier that is classically unsurmountable ”.

Schrodinger equations when solved and analyzed, it indicate that the nucleus has a probability that it can fuse with other nucleus and this probability goes on increasing as the kinetic energy of colliding nuclei increases. They explain it like the overlapping of the waveforms that represent the two nuclei.

Again you have to agree with this description because here is series of examples of the applications of quantum tunneling: nuclear fusion in stars, tunnel junction, tunnel diode, tunnel field-effect transistor, quantum conductivity, scanning tunneling microscope, quantum biology, etc.

PHENOMENON IN STARS

Nuclear fusion can be called the ultimate source of energy of the universe. Stars are powered by this and virtually all the atoms (elements) are produced in this process which is also called stellar nucleosynthesis. The type of fusion reaction followed depends on the mass of the star, the pressure, and temperature of its core.   

If we consider our own star the sun then it utilizes the nuclear fusion of hydrogen into helium at 14 million kelvin core temperature. 620 Million tons of hydrogen per second fuses to form 606 Million metric tons of helium each second. The net rate of mass-energy conversion is 4.26 million metric tons per second, which produces the equivalent of 38,460 septillion watts (3.846×1026W) per second, this really very hugeeeee!!!!!!

NUCLEAR FUSION: How much it takes to mimic a star ?

STAR MIMIC :

THE DEUTERIUM-TRITIUM REACTION:NUCLEAR FUSION: How much it takes to mimic a star ?

We are looking for this reaction because it is the most feasible and reactants are easily and abundantly available. Considering the fueling up of smaller atoms with kinetic energy to break the Coulomb barrier, scientists have chosen single proton species to bang together. The reaction deuterium-tritium seems to be a perfect choice.

NUCLEAR FUSION: How much it takes to mimic a star ?

The DT rate peaks at a lower temperature (about 70 keV, or 800 million Kelvin) and at a higher value than other reactions commonly considered for fusion energy on earth.

FUELS:

  1. Deuterium: 1 in 5000 of hydrogen in seawater is deuterium (a total of 10^15 tons). Viewed as a potential fuel for a fusion reactor, a gallon of seawater could produce as much energy as 300 gallons of gasoline.
  2. Tritium: is little problematic. It is radioactive with a half-life of about 10 years hence no source of tritium is present on earth. This is obtained from breeding lithium with is abundant. Sometimes I just remain awestruck by the efforts and adventures of humans, it has been planned to establish a mining factory on the moon and transport helium isotope to earth via rockets in the future.

INPUT AND OUTPUT ENERGY:

In this reaction, deuterium and tritium isotopes of hydrogen are first ionized to become bare nuclei. The calculated coulomb barrier is  0.1 MeV. After crossing this limit the immediate result of fusion is the unstable 5He nucleus, which immediately ejects a neutron with 14.1 MeV. The recoil energy of the remaining 4He nucleus is 3.5 MeV, so the total energy liberated is 17.6 MeV. This is many times more than what was needed to overcome the energy barrier hence the result is net energy output.

NUCLEAR FUSION: How much it takes to mimic a star ?

PROCESS STEPS:

  1. Stage one heating: once the atoms are heated above its ionization energy, its electrons get stripped away, leaving behind an ion.
  2. Stage two heating: continues until the Coulomb barrier is not reached. The result is an extremely hot cloud of ions and electrons. This is known as another state of matter, the plasma. The state is electrically and magnetically responsive due to separated charges. Many devices take advantage of this to control plasma.

Plasma is thus magnetically and electrically responsive. In bulk its modeling is done using the science of magnetohydrodynamics, this is the combination of the motion of fluid governing equation the Navier Stokes and electric and magnetic field behavior governing equations called Maxwell’s Equations.

Now the problem is how to confine the extremely hot plasma. There doesn’t exist any material which can stand firmly at 300 Million kelvin, that doesn’t degrade by the constant bombardment of high energy neutrons and other particles.

WHAT IS THE MECHANISM?

There are two famous approaches to do this:

1. MAGNETIC CONFINEMENT

2. INERTIAL CONFINEMENT

  1. Magnetic confinement: We know that plasma is charged with help of strong superconductor magnets they can be hanged up in the vacuum without actually touching the walls of the container. This concept is called magnet mirroring. 

 

ITER (International Thermonuclear Experimental Reactor), in Latin ITER, means”a way”, a prestigious organization having headquarters in France established in 2007, its members include India, US, Russia, China, Japan, Korea, and the Euratom. Its purpose is to research and demonstrate the technological and feasibility of fusion energy for peaceful purpose. The ITER employs a mega machine called tokamak. The stellarator is also one of this kind. Here is an awesome video to make the mega monster easy to understand:

2. Inertial confinement: Fusion is achieved by compressing and heating fuel pallet. Mega Intense laser beams rapidly heat inside surface of hohlraum. The fuel is compressed by rocket-like throw-off of the outer surface material. Finally, the fuel is ignited at a temperature of about 100,000,000 degrees Celsius. And the NUCLEAR FUSION occurs producing far more energy than taken by the laser system in the beginning.

NUCLEAR FUSION: How much it takes to mimic a star ?

Just as ITER pioneers the magnetic confinement the NIF (National Ignition Facility, California, US) leads the way in inertial confinement fusion. Here the short clip on that:

DISADVANTAGES:

  1. Tritium is radioactive and also difficult to retain completely. Hence some amount of tritium would be continually released. The health risk posed is much lower than that of most radioactive contaminants, because of tritium’s short half-life (12.32 years) and very low decay energy (~14.95 keV). It also doesn’t accumulate in the body (its biological half-life is 7-14 days).
  2. The cost involved is enormous in research, instead if we invest in proven technologies then it would be the sure shot. Investment in the nuclear fusion is billion-dollar dollar gamble surely.
  3. In my opinion just as human discovered vaccines which in turn increased the average human life and hence population on earth banged in numbers, in same way limitless energy would cause the steep rise in population, the economy would entirely be changed because markets would no more depend on the rates of oil.

ADVANTAGES:

  1. The half-life of the radioactive waste is quite less as compared to the fission wastes which have thousands of years as half-life more over less toxic than emissions from fossils fuel burning.
  2. The energy supply would be uninterrupted and provide service to humans for millions of years!
  3. No greenhouse gas emissions, no global warming and zero environmental concerns in any way round (air, water, and land).
  4. No hike in energy supply cost around the fiscal year.
  5. Those importance processes which are high energy intensive can be carried at low cost like desalination of seawater for the availability of fresh drinking water.

CONCLUSION:

Here is a quote from one of the greatest physicist of the 20-th century:

NUCLEAR FUSION: How much it takes to mimic a star ?

So, there is no doubt that it was the feats of our earlier scientists and engineers who led us to where we are today and it is we who will decide the future of human civilization, and we must be happy that we are putting the efforts at an incredible rate, and till then we have to make sure that we too at individual level are playing our assigned role in this universe of the “ALMIGHTY”.

“You have patience level 10 if you have read the whole article because it is quite lengthy although keeping it short has been tried “-Rahul

Thanks for your time and patience.

Keep reading, stay blessed!

TEAM CEV

HIGGS BOSONS : Giving Universe the Mass

Reading Time: 8 minutes

In the introduction to this massive ~1600 words blog, I must let you know that this blog intends to ignite or thrill some of the interested minds by discussing how we the humans have understood the universe till now, how the path-defining experiments have to lead us to understand the universe as it is. This blog is about the Nobel prize-winning theory, the existence of the Higgs field, the experiment that had cost $13.25 Bn, the results of experiments, the conclusions, and the aftermaths.

HIGGS BOSONS : Giving Universe the Mass

To understand this science of the universe just like 2 + 2 = 4 we have to start by understanding the standard model and its flaw in the 1960s.

So let’s start with the standard model.

HIGGS BOSONS : Giving Universe the Mass

THE STANDARD MODEL :

All the particles in this universe can be divided into just two categories namely – Elementary and Composite particles. Elementary particles are those which are the fundamental one, means they are not made up of further any basic particles as per now. Combining them we get composite particles.

Elementary particles are then categorized into particles having half-integer spin, the fermions and with integers spin, the bosons.

Now the fermions are further divided into two on basis of whether they interact by a fundamental force called the strong interaction or not.

You must be knowing that there are only four fundamental forces in nature, strong interaction, weak interaction, electromagnetism, and the gravitation.

So all those fermions that interact via strong force are called quarks and those who don’t are called leptons. In the quarks category, we have six flavors up, down, top, bottom, charm and strange. In leptons, we have electrons, anti-electron, neutrino, and anti-neutrino.

Now comes the bosons. The elementary particles having integer spin also called the force particles, they are the particles that are responsible for the mediating forces between particles. The strong interaction mediated by gluons, weak interaction by W and Z bosons, electromagnetic interaction by photons and gravitons are responsible for the gravitation.

I have plotted the scene for the story, now let’s begin it. So, the quarks which can interact by strong interaction by exchanging gluons, come together to form composites like protons (uud) and neutrons (ddu) which can be electrically charged or neutral one, these protons and neutrons combine together by virtue of residual force of strong interaction, to form nucleus, it is positively charged and now negatively charged leptons, like electrons begin to get attracted and form orbits around it. This is the way atomic physics work.

But one thing could not be explained by the standard model, what is the reason behind why particles like quarks and electrons have mass whereas particles like neutrino and force carrier particles (the bosons) don’t have mass?

THE HIGGS FIELD THEORY:

The pioneering team of physicists Peter Higgs and 6 more came come with an extension to the standard model, the new type of boson called HIGGS BOSON to explain why some particles have mass whereas some don’t. So according to the theory mass is not the fundamental property of all particles, but there is some ubiquitous field that permeates in the whole universe which gave the effect of mass or inertia to some particles.

This purely hypothetical field was given the name of the Higgs field. Some of the particles like electrons, quarks, protons, neutrons, etc, interact with this field strongly and exhibit what we feel as inertia and mass. And here we go, the more an object has these type of particles, the more interaction with the field is there and hence more massive it becomes.

One more concept from the quantum theory, “every particle is a disturbance of its corresponding field”, that why Schrodinger talked of the probability distribution. For example, quarks are disturbances of the gluon field, electrons are a disturbance of the electric field and analogy to that Higgs Bosons are the disturbances of the Higgs field.

I know that it might be sounding very crummy, but if you have reached here then you must not leave till the end.

EXPERIMENT OF MILLENNIUM: THE LARGE HADRON COLLIDER 

So the experimental physicist and the engineers at a European organization of Nuclear Research, CERN (derived from the name Conseil européen pour la recherche nucléaire), in Geneva, Switzerland, began to set experimental setup for an experiment that predicted to establish the Higgs field theory by confirming the existence of the Higgs boson.

HIGGS BOSONS : Giving Universe the Mass

Here comes the major part of this blog :

AIM OF EXPERIMENT:

The scientists have with them the theory of the Higgs field, to prove it is correct, they had to show the existence of the Higgs Bosons. Considering the Einstein energy-mass equation, E = mc^2, if we can make the elementary particles cruise at speeds close to that of light and make them collide than there are chances that the kinetic energy may convert to new elementary particles never seen before, like the Higgs bosons.

After detailed study and simulations of the collision, it was indicated by the quantum mechanics that about 90% of all the Higgs boson that would be created in collisions would be produced by gluon fusion phenomenon. Gluon fusion results differ by around 20% which can be taken as the theoretical uncertainty of the gluon structure, and the chances of two gluons colliding, give rise to Higgs boson is 1 in 2 billion. However, in this experiment approximately 1 billion proton collides every second, hence the production rate for Higgs bosons is roughly one in every two seconds, which is not at all discouraging.

THE GIGANTIC NUMBERS OF LHC :

World’s largest and most powerful machine made by humans, has spectacular numerical parameters associated with it. The protons need to haul at 0.99991c hence chambers need to be close to perfect vacuum, to avoid collision with any gas molecule. Data literally would be flowing every microsecond hence the need to store and analyze it, all these require engineering at a phenomenal level. The different sections include powering, accelerating, steering and focusing, cooling, storing and computing work in sync surely earns it the tag of greatest effort by the human being to understand the mother nature.

HIGGS BOSONS : Giving Universe the Mass

1. The machine consists of a tunnel 27 kilometer in circumference and as deep as 175 meters located at France-Switzerland border.

HIGGS BOSONS : Giving Universe the Mass

2. The energy requirement is pretty high. Estimate of 800,000 Megawatt hours (MWh) annually that cost around $30 Million per year, which is enough energy to power 300,000 homes throughout the year, is consumed.

HIGGS BOSONS : Giving Universe the Mass

3. The magnets are very large, weighing several tons. They steer protons at 99.99% the speed of light. They are cooled down to 1.9 K (-271.25 degree Celsius), that is colder than the vacuum of outer space!

HIGGS BOSONS : Giving Universe the Mass

4.  This machine has six points for observation, each loaded with microscopes and digital cameras. Microscopes measuring 45m long, 25m tall and weigh about 7000 Tons.

HIGGS BOSONS : Giving Universe the Mass

5. Nearly 150 million sensors collect data during experiment generating data at about 700 Megabytes per second (Mbps). On a yearly basis, 15 Petabytes (15 million Gb) data is stored at CERN. To tackle with this problem Sir Tim Bernes Lee with engineer Robert Cailliau invented world wide web in 1989 to distribute data to university and labs around the globe to store and analyze and form the platform to discuss and share.

THE EXPERIMENT BEGINS :

  1. Hydrogen atoms at very precisely controlled rate enter the source chamber of the linear accelerator. Under high strength electric field, they are converted to bare hydrogen nuclei, the proton.
  2. To intensify the beam and give them further acceleration, they are directed into circular boosters, as linear accelerators can’t be made so long.
  3. Using oscillating electric field the kinetic energy is pulsed into the beam, the perpendicular magnetic field helps them to rotate in a circular path.
  4. The beam goes through proton synchrotron (PS) and super proton synchrotron (SPS) to get further intensified and energized. When it enters the 27 km long circular tubes they have velocity 99.99 % of “c” and energy of 450 GeV!
  5. Sophisticated kickers make the two beams exit the SPS and travel through the two 27 km long tubes in opposite direction. The pulsed electric field continues to add energy to them and large superconducting magnets are employed to rotate these particles at such speed.
  6. The velocity just before the moment of collision is only 10 kmph less than the speed of light! The collision confines a very-very large amount of energy (2*7 Tera eV) in very-very tiny space of the volume. Energy has no other option other than to convert into mass, E = mc^2 comes into action, and a wide range of interatomic particles are formed out of huge energy.

Result analysis:

On 14 March 2013 CERN confirmed that:

“CMS and ATLAS have compared a number of options for the spin-parity of this particle, and these all prefer no spin and even parity [two fundamental criteria of a Higgs boson consistent with the Standard Model]. This, coupled with the measured interactions of the new particle with other particles, strongly indicates that it is a Higgs boson.” ~CERN

The Higgs bosons as predicted was highly unstable and decayed in 10^-22 seconds into pairs of photons (γ γ), W and Z bosons (WW and ZZ), bottom quarks (bb), and tau leptons (τ τ) which was perfectly consistent with the Standard model! Hence led to confirmation of the presence of the “HIGGS BOSONS“!

Following are extended results for strong support, for further reading:

https://docs.google.com/document/d/1V8HkMjAcDEVukqUUuROC8qZCT-m04LImsmBBFCAOoPs/edit?usp=sharing

 To get better about LHC, follow the beautiful video :

Conclusion: First of all the effort and initiative taken by this organization, CERN should be appreciated. Also, this feat can serve as a great source of inspiration and motivation for the new generation of engineers and physicist. This experiment gave us the internet (www) and opened for us a huge source of knowledge. Moreover, the results of this experiment help us to understand the mother nature more closely, and these results might serve in the future for the advancement of science, here on EARTH! 
In the end a huge thanks for the time and patience.
Writer will feel appreciated if you follow by a question!
Thank you.
TEAM CEV’
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