The impact of reversing a standard method has been discovered by scientists. Theorists at the U.S. Department of Energy have proposed doing the opposite of the procedure they were told to do.
There are holes in the material.
All today's tokamaks, doughnut-shaped magnetic facilities designed to create and control the virtually unlimited fusion power that drives the sun and stars have locked tearing modes. The fourth state of matter composed of free electrons and atomic nuclei that fuels fusion reactions and tear holes in the magnetic field allow the leakage of key heat.
These islands grow larger when the modes stop rotating and lock into place, a growth rate that increases the heat loss, reduces the performance and can cause disruptions that can damage the tokamak's inner walls. Researchers beam microwaves into the plasma to make sure the modes are stable.
The findings suggest that the modes in large, next- generation tokamaks are stable after they lock. "In today's tokamaks, these modes lock more quickly than people had thought and it becomes much harder to stable them while they're still rotating," said Richard.
He said that the microwaves increase their width by refracting off the plasma, making the stabilization of the mode even less efficient because it's rotating even less efficient.
In large future tokamaks like ITER, the international facility under construction in the south of France, "the rotation is much slower and these modes lock pretty quickly when they're still pretty small." It will be easier to switch up the stabilization package in a big future tokamaks.
The fusion process could be aided by that reversal. The process releases a lot of energy with the help of light elements. Allan Reiman, a research fellow and co-author of the paper, said that this provides a different way of looking at things and could be a more effective way to deal with the problem. Allowing the islands to lock should be taken more seriously by people.
It's close to disrupting.
Because tearing mode islands grow so fast and are so large when they lock in these facilities, the recommended technique is unlikely to work in today's tokamaks. At the cost of limiting fusion output, researchers need to use large amounts of power. The mode is stable because of the slow growth of islands in next- generation tokamaks.
When the modes in future tokamaks are locked in place microwaves will be able to target them directly, instead of stabilizing them. The efficiency of the proposal is shown by the theoretical calculations.
Experiments are required to test the course of action. We don't want to turn on ITER until we know which strategy works. There is a chance to look at the physics in current devices.
More information: Richard Nies et al, On the stabilisation of locked tearing modes in ITER and other large tokamaks, Nuclear Fusion (2022). DOI: 10.1088/1741-4326/ac79bd
All Rights Reserved © 2024
