Helium-3 is a rare isotope of a very common element on the Sun. Recently, scientists have noticed a region on our luminary from which its particles come tens of thousands of times more than is normally observed.
Excess helium-3
Recently, a team of SwRI scientists reported that they found something interesting in the Solar Orbiter spacecraft data. As indicated in their study, published in The Astrophysical Journal, this vehicle studied high-energy particles flying from the Sun and noticed extremely high numbers of helium-3 ions among them.
Helium is one of the most abundant elements in the universe. It is usually represented on stars by an isotope with an atomic mass of 4, meaning it has two protons and two neutrons in its nucleus. But there is also a variety that has one less neutron. It’s called helium-3.
Usually, helium-3 is only an intermediate product of the thermonuclear reactions that power stars. Therefore, its amount in the Sun is very small. Usually there are 2500 helium-4 ions per 1 ion of this isotope.
At the same time, it is of great interest to scientists and not only because of the fact that it is a potential thermonuclear fuel. Also, because of its high charge-to-mass ratio, its particles can sometimes be accelerated more strongly than other atomic nuclei.
Unusual sunspots
However, in at least one case, Solar Orbiter recorded a helium-3 ion flux 200,000 times denser than normal. In addition, the velocity of the particles was much higher. What was the source of such an unusual flux? NASA’s Solar Dynamics Observatory provided insight into this question.
The source turned out to be a small region at the edge of a coronal hole, the place where the Sun’s magnetic field force lines break and bend into space. The detected site was special because the magnetic field strength in it turned out to be anomalously low. It looked more like the calm regions of our star than the places where flares are born.
According to scientists, it was the low magnetic field strength that contributed to the enrichment of the plasma with helium-3 particles, which were then ejected into space. In addition, the concentration of iron ions usually increases in such places. But not in this case.
On the contrary, oxygen, sulfur and other light elements were present at the detected site. Scientists admit they can’t figure out everything that’s going on yet and are hoping for further observations.
According to phys.org
