Researchers have uncovered a groundbreaking method to manage plasma density in fusion reactors, a critical step towards unlocking the full potential of fusion energy. By leveraging the anisotropic nature of energetic ions, they have found a way to regulate the inflow and outflow of particles, paving the way for enhanced reactor performance and more efficient energy production.
Utilizing Energic Ions
The triad of plasma density, temperature and heating are fundamental to achieving fusion energy. Plasma particles and heat must be confined for sufficiently long times to allow the fusion reactions to occur at practical rates and generate net power.
By using energetic ions (whose distribution is anisotropic), researchers at the Large Helical Device (LHD) have found a new way to control the density profile in the plasma. By tuning the ratio of the stored energies in perpendicular and parallel to the injection beam power components it has been possible to affect the velocity distribution of energetic ions, producing large changes in electron density and carbon ion density profiles.
Why Flat is Peaked: The Power of Anisotropy
They were able to observe that, for an En⊥/En|| ratio below 0.4 the electron density profile either remained flat or even hollowed at the center. However, this peakedness only occurred when this ratio was greater than 0.4.
It is an observation that the plasma inflow and outflow rates might be increased or decreased by the energetic ions. Simulation calculations also implied that the electric field at -5 kV/m in radial direction at center of plasma core, will not greatly affect particles transmission. Rather, the scientists argue turbulence might be important for setting what is known as both peaked and flat density profiles.
It is this truly groundbreaking discovery that demonstrates the incredible ability to use ions in an anisotropic state to direct and control the flow of particles inside a fusion plasma so as to indefinitely maintain the plasma in a perfect state of optimal operation corresponding to maximum systematic performance.
Conclusion
Scientists take a step toward control of the plasma density in fusion reactors Manipulating the inflow and outflow of particles is one of the keys to achieving high-performance, steady state in ITER—therefore this experiment has opened up an important new operation window in burning plasmas for ITER and reactor plasmas. This is an important step on the path to unlocking fusion energy, which will one day provide a virtually limitless supply of clean and safe power for our planet.
