streaming from At a million miles per hour, the Sun, the solar wind—a violent plasma of electrons, protons, and ions flowing through space—is a decades-old mystery. Scientists know it once robbed Mars of its atmosphere, and some believe it put ice on the Moon. Today it causes flashes of auroral displays and ruins satellite communication systems.But researchers were unable to pin down how The solar wind is created and heated or accelerated to millions of degrees to fill the entire solar system.
A team of researchers now think they have it figured out. According to them, the solar wind is driven by jetlets. These are small intermittent explosions in the Sun’s upper atmosphere or the base of the corona. The theory is just published of astrophysics journalwas born from data acquired by NASA’s Parker Solar Probe. The Parker Solar Probe is a car-sized satellite that has been flying close to the Sun repeatedly since 2018. It measures the properties of the solar wind and tracks the flow of heat and energy in the outermost part of the Sun’s atmosphere. It begins approximately 1,300 miles above the surface. The team’s idea, bolstered by data from other satellites and ground-based telescopes, suggests that jetlets are ubiquitous and might be powerful enough to explain the mass and energy of the solar wind. Doing so will help scientists better understand how stars work and predict how plasma blast streams might affect life on Earth.
Higher resolution data are needed to prove this hypothesis, but the evidence so far is intriguing. “Early on, we knew we were on to something big,” said Noor Lauafi, an astrophysicist at the Johns Hopkins University Applied Physics Laboratory who led the study. We thought we might be solving a 60-year-old puzzle of the solar wind, and we believe it is.”
The existence of a solar wind was first proposed by the late Eugene Parker (hence the name of the Parker Solar Probe) and confirmed by NASA in the early 1960s. Since then, scientists have puzzled how plasma can travel so far and so fast. The sun’s corona is millions of degrees hot on all temperature scales, but not hot enough to push the solar wind up to that speed.
Jetlets, on the other hand, were not discovered until 2014. study We show that these small explosions, led by Raouafi, drive coronal plumes, bright funnels of magnetized plasma near the solar pole. Looking closer at the base of the volcanic plume, they found that the plume is created when the rotating surface of the Sun forces two regions with repulsive magnetic polarities to fuse and rupture. After that his thesis, however, Raouafi moved on to other projects. “And we basically left it there,” he says.
And in 2019, when Raouafi was working as a project scientist for the Parker Solar Probe, the rover saw something strange. When skimming the top of the corona, we observed frequent reversals of the direction of the magnetic field during flight. Then it will tip over. Raouafi assembled a team to find out what caused these intermittent “switchbacks” in the atmosphere. His heart immediately went to Jetlet. He reasoned that if they were found elsewhere in the corona, not just in the plume, there might be enough of them to produce enough matter and power. become the solar wind itself.
