As the tokamak heats up, scientists must control the runaway plasma

  • Fusion researchers are working to raise energy plasma in their reactors so they can generate more power using smaller tokamak equipment.
  • When the plasma diffuses into this highly active state, it can explode against the walls of Tocamexwhich leads to damage to its internal components.
  • A new study conducted in Korea shows that magnetic controls can successfully manage these blasts, resulting in smoother flow and reduced maintenance.

    Plasma inside tokamaks – the doughnut-shaped organs that can contain nuclear fusion reactions – can be difficult to manage.

    Spikes of super-hot plasma, similar to Solar flares That erupts from the surface of the Sun, comes from a system operating at a high energy level. These mutations can lead to overheating of the internal components of the tokamak. (Plasma is formed by heating gas until it ionizes. All nebulae, aurora, and lightning contain glowing plasma.)

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    striving for stability fusion Interactions An international team of physics researchers has developed a sophisticated set of magnetic controls to reduce plasma bursts that can damage tokamaks. that they publish their work Earlier this year in the magazine Plasma physics.

    Plasma instability

    inside tokamak, Deuterium, which is an isotope of hydrogen, circulates at a very high temperature and at a low density. There may also be tritium, a second isotope of the same substance. Isotopes of an element have a different number of neutrons in their nuclei than each other, but the same number of protons.

    The plasma nucleus of the tokamak can be 100 million degrees Celsius, Ejmeen Colemanan associate professor in Princeton University’s Department of Mechanical and Aerospace Engineering and a co-author of the paper, says popular mechanics. The wall temperature ranges between 400 and 1260 degrees Celsius.

    Deuterium travels around the circular ring. The hoop is inside a heavy-duty exterior enclosure. Electromagnetic forces direct deuterium along its path. In the event of plasma instability, such as in edge-finding modes, ions can damage the interior of hoop.

    Coleman explains that the edge-defining patterns “are bursts of energy” that appear at the end of the plasma and hit the wall. “These explosions lead to massive increases in heat load on the wall of the machine.”

    In early fusion research, localized edge patterns did not occur because plasma It was in a lower power state. In recent years, fusion researchers have found it beneficial to run the tokamak in a higher power mode, known as “H mode,” because it produces better performance in a small size. However, in H mode, deuterium becomes more difficult to control.

    “We want this high mode, but we don’t want this instability that leads to this burst of energy that increases heat and maybe melts the wall,” Coleman said.

    Calm down localized edge modes

    The sun close-up shows the activity of the surface of the sun and the corona

    An image showing the surface of the Sun and the activity of the corona, the outer part of its atmosphere. Plasma spurts are similar to solar flares emanating from the sun’s atmosphere.

    DrPixelGetty Images

    Fusion researchers have experimented with a variety of methods to smooth out the edge localized modes. These include adding other gases, Coleman says. The paper also shows that scientists have attempted to inject hypersonic particle beams, using small periodic displacements of vertical equilibrium, and more.

    Coleman and colleagues, for their part, used a control device that disturbed the plasma. “We were looking at using 3D files,” he says. “We have these… structures. They are like windows around the reactor on the torus. They make electricity and magnetic fields asymmetric with respect to the cross section of the plasma. What you do with this 3D perturbation is you can change the stability of the edge. You can make localized edge modes disappear. That’s great.”

    These disturbances make plasma confinement difficult, unfortunately. This is where the dynamic controls come into play. The controller adjusts the magnetic fields so that only 10 to 20 percent of pressure is lost.

    “We’re basically trying to determine the sweet spot and then adjust the plasma.”

    “We have a plasma simulation that we use,” Coleman explains. “We built an intelligent control system that looks at the plasma and adjusts the 3D turbulence and then sees what the plasma is doing. It looks at everything and adjusts the control. We’re basically trying to determine the sweet spot and then fine-tune the plasma. Ultimately, what you achieve in the end is the highest possible pressure of the plasma but without The instability of the edge. We got much better results. We got rid of the instability, but we still stay in the big confinement.”

    The paper says the reagent has some false positive and false negative results during experiments, so it should be replaced with one that does not depend on the tuning for the calibration.

    “I think, basically, I have faith that people are going to discover some of these technical challenges,” Greg Beaverfounder and CEO of SHINE Technologies, says popular mechanics After reading the newspaper. “They’re tough. They’re going to be very expensive machines, at least with today’s technology. You’ll need to compete with other energy sources. If you have to build a really complex machine with a lot of exotic materials, cutting the cost is going to take some time. You’re going to have to create really good economies of scale. Really good supply chains.”

    Beaver said he is optimistic about the future ability of fusion to power us electrical network. “I think, in the long run, it’s the way humans produce energy. We’re at a tipping point now. It’s exciting to be here now and help usher in what we call the age of fusion.”

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