100 Nano-Stories: What is Fusion?

Episode #05: Fundamental Concepts of Fusion Energy!

Carlos Manuel Jarquín Sánchez
5 min readJan 2, 2021


Hello, reader! Hope you had a wonderful New Year Day! I’m guessing from all those face-time calls on WhatsApp and DM’s, you have to charge your phone to the full battery! Now, it may take a while, but if only we had some sort of power source that could generate so much energy for decades!

Wait, Carlos, how did you know I was charging my phone/computer? And what do you mean that we have a new energy source? Is this another of your tricks?

No! There is an idea to bring clean power for decades to come! Welcome…

Fusion Energy!

Uh, Carlos, what is fusion?

Fusion is two or more atoms joining and combining to become a new atom/molecule, and in the process, it will release a lot of energy! This is the same process that powers all the stars in the universe! Our Sun, for example, is a Yellow G2 Star that fuses 600 million tons of hydrogen into 596 million tons of helium. The remaining 4 million tons are converted into pure energy!

4 million tons of energy! Well, what are we waiting for? Let’s go make some fusion energy for all!

Uhh.. not so fast, dear reader! You see, making nuclear fusion on Earth is very difficult to sustain. The reason nuclear fusion works in the sun is because of the forces that govern fusion and the temperatures require to create fusion. The nuclear forces can only be maintained/sustained in high density & high-temperature environments. Speaking of Earth, if we want to make nuclear fusion here on Earth, we would need to take the temperature of our fusion reactor very hot.

How hot, Carlos?

How does 100 million degrees Celsius sound to you?

On Earth!!!… Photo by TV Tropes.

Another reason why we need to reach 100 million degrees Celsius is that we need the forces of the atoms to surpass their repulsion from one another and force the protons to fuse. Protons are positively charged, and like things repel. So that is why we need this high temperature to overcome their repulsion.

Once this happens, the high density & high temperature allows us to make something that is known as plasma, a high-energy state of matter. This is when protons are stripped from their electrons and are moving freely at very high speeds.

Isn’t that also the 4th state of matter, Carlos? 🤓

Yes, reader… Anyways, moving on!

Wait, Carlos, can you describe quickly how Fusion is supposed to work?

The Coulomb Force!

The what-what? I thought it was gravity!

Hold on, reader! Now you’re acting like those free protons!

Normally, two hydrogen atoms have to collide with one another to fuse into helium and release a lot of energy in the process. But to begin with, the Sun was not born from anything; it required leftover energy to create itself and nuclear fusion.

But what atoms or particles are we talking about, Carlos?

In hydrogen, we are talking about protons! Some isotopes of hydrogen, like deuterium and tritium, have neutrons in their nucleus. Normally, these atomic nuclei don’t want anything to do with one another! But this is when the Coulomb Force comes into play!

The Coulomb Force is what prevents the atomic nuclei from colliding with one another.

So does that mean, they have to be going very fast at very high temperatures in order to overcome the Coulomb Force?

BINGO!!! Good job, reader!

No more confusion! 😉 Photo by Open Access Government.

Hey, Carlos, didn't you briefly talk about deuterium & tritium? Can you tell me a little bit more about that?

Deuterium, Tritium, and Setbacks

Deuterium is an isotope of hydrogen with one proton and one neutron in its nucleus. Tritium is an isotope of hydrogen with one proton and two neutrons in its nucleus. These two isotopes of hydrogen are commonly used when producing fusion energy/fuel here on Earth.

But why not regular hydrogen? The one with only one proton in its nucleus?

The reason why we do not use hydrogen is that regular hydrogen cannot be conceived at a smaller scale. But guess what? We also do not prefer the deuterium-deuterium reaction.

Why not, Carlos?

Because a deuterium-tritium reaction reacts approximately 20 times higher than a deuterium-deuterium reaction. The only problem with this is that tritium is very rare to find on Earth, so having enough tritium to make fusion energy a viable energy source would be very complicated.

Is there any other problems with fusion energy?

There are a few problems, unfortunately. Some of these problems are:

  • It takes more energy to make fusion energy work than what we get back in exchange.
  • Remember how I talked about 100 million degrees Celsius? Well, isn’t that a huge problem? How are we supposed to heat something, contain the plasma, and maintain something hotter than the surface of The Sun?

Hmmm… you are right! That is hard to maintain! Can you talk about the current methods of how we are trying to achieve fusion energy?

That sounds like a wonderful idea for the next article! 😉

Definitions 📓

Nuclear Fusion - the reaction in which two atoms of hydrogen combine, or fuse, to form an atom of helium. In the process, some hydrogen can be converted into energy.

Proton - a stable subatomic particle occurring in all atomic nuclei, with a positive electric charge of +1.

Neutron - a subatomic particle of about the same mass as a proton but without an electric charge, the charge is 0. It can be found in all elements except Hydrogen-1.

Deuterium - an isotope of hydrogen with one proton and one neutron in its nucleus; Hydrogen-2.

Tritium - Tritium is an isotope of hydrogen with one proton and two neutrons in its nucleus.

Plasma - an ionized gas where positively charged particles (ions) and negatively charged particles (electrons) roam freely.

Coulomb Force - also known as electrostatic force, or Coulomb’s interaction, attraction, or repulsion of particles or objects because of their electric charge. In this case with fusion energy, the interaction is repulsive because protons are positively charged, and fusing like charges will repel.

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© 2021 by Carlos Manuel Jarquin Sanchez. All Rights Reserved.