Last week’s classroom time was replaced by an opportunity to visit the Plasma Science and
Fusion Center located on MIT’s campus. Upon arrival, we were ushered into a conference room to receive a preview to the fusion center’s tour, as well as new facts concerning nuclear fusion and the MIT center itself. Our presentation leader began by reiterating the now-familiar yet unfortunate truth that the Earth’s reserves of fossil fuels will not last much longer, considering its high demand. In recent years, alternative fuel sources have been discovered and used for experimentation with differentiating results. As promising as these alternatives may seem, the perfect option is nuclear fusion as it “cuts out the middle man” in its energy production process. However, the completion of this process is far from simple; doing so involves harnessing the same energy as the Sun, requiring the use of the fourth state of matter, better known as plasma.
When energy is added to matter, the particles move rapidly and, depending on how much is applied, the matter can change forms – from solid to liquid, gas, and finally plasma. A new term learned from this presentation is the definition of an electron-volt (eV) and its definition as the electron’s kinetic energy during acceleration through an electric potential difference; according to the informative slide, an electron’s energy level at 1 eV is equivalent to 11,330 °C, or 20,400 °F (used for measurement only in Belize, Burma, Liberia, Palau, and the United States). In a plasma atom, the negative energies of the two electrons cause them to repel each other constantly, yet attract them to the nucleus. Examples of plasma can be spotted nearly anywhere in the universe as most visible matter in space, such as the Sun, is comprised of plasma. Here on Earth, plasma is used in televisions, lightbulbs, and even cell phones; most importantly, in terms of our presentation, plasma is used at MIT to conduct magnetic fusion.
As we had learned in a previous class, the act of fusion is caused when two isotopes of hydrogen, deuterium and tritium, come together to produce 17.6 MeV of energy. Magnetic fusion employs this process while confining the nuclei and electrons within a magnetic forcefield thanks to the Lorentz force. The donut-shape of the tokamak, or the vessel that contains this activity, closes the magnetic field lines with its shape of consistency, ensuring that the scorching plasma will not touch the sides of the machine.
Of all the locations using magnetic fusion, the Alcator C-Mod, of which we were given a tour following the conclusion of our presentation, contains the highest magnetic field and could produce the energy source needed to eliminate the dependency on fossil fuels; however, the dismal fact remains that the act of harnessing energy from nuclear fusion has yet to be done. This is mainly due to the lack of usable earthly material that will not melt under the extreme temperatures needed for nuclear fusion. Scientists around the world, including those employed in the development of the MIT Alcator C-Mod tokamak, are working towards the day when nuclear fusion will become a safe and reliable source of global energy. However, the future of the Plasma Science and Fusion Center, as well as the Alcator C-Mod, is in danger of being shut down by opposition within the federal government. To ensure that the scientists at MIT can continue their progress towards successful nuclear fusion, please visit this link to sign the supportive petition.