A year ago, NASA’s Solar Parker Probe became the closest satellite ever to the Sun, collecting a precious set of data, from its position on the edge of the solar corona, withstanding temperatures of one million degrees. .
Now, that data has allowed solar physicists to map the source of a major component of the solar wind that continually splashes into Earth’s atmosphere. Furthermore, they have revealed a strange behavior of magnetic fields that could be sending particles towards our planet.
For the first time, scientists can study the solar wind from its source, the Sun’s corona, in a way similar to how a river flow might be observed.
NASA has released four new documents that provide hitherto unknown (only theorized) characteristics of the volatile star that presides over our solar system.
The origin of the ‘slow’ solar wind
The Parker solar probe has been able to study the source of the solar wind and see how it progressively accelerates in the hot atmosphere of the Sun.
The solar wind is made up of charged particles, primarily protons and helium nuclei, that travel along the lines of the Sun’s magnetic field.
Scientists had theorized that the so-called “fast” solar wind, which has a clock speed of between 500 and 1,000 kilometers per second, comes from large holes in the solar corona at the north and south poles. But the origin of the “slow” solar wind, denser and roughly half the speed of the “fast” solar wind , was much more unknown.
Now, thanks to observations from the Parker probe, scientists have been able to trace the solar wind and magnetic fields back to their source: coronal holes. These, which are related to sunspots, are cooler and less dense areas than the surrounding corona.
“We can see the magnetic structure of the corona, which tells us that the solar wind is emerging from small coronal holes,” explains Stuart Bale of the University of California, Berkeley, professor of physics and lead author of a paper on the new results. from the probe’s FIELDS experiment. “In addition, we see impulsive activity: large jets or flashbacks that we think are related to the origin of the solar wind , we see the instability of the gas itself, which generates waves.
“We are also surprised by the ferocity of the dusty environment in the inner heliosphere ,” he adds.
Credits: NASA / SDO
Somersaults in the magnetic field
The most unexpected thing about the data was a series of somersaults in the magnetic field, which the Parker probe observed as it passed.
It is the behavior of the solar wind within the orbit of Mercury, and that alters the direction of the magnetic field that flows from the Sun. During this event, the magnetic field turns on itself until it points almost directly towards the Sun itself. Researchers: ” It suddenly reversed 180 degrees and then seconds to hours later it went backward .”
These observations help us understand what causes solar winds, what heats them up, and also how stars work and how they release magnetic energy into their surroundings.
“These interruptions are probably associated with some kind of plasma jets,” Bale explains. “My feeling is that these interruptions or jets are fundamental to the problem of solar wind heating.”
Rotating solar wind
In a post, the researchers found surprising clues about how the Sun’s rotation affects the outflow of the solar wind.
Close to Earth, the solar wind flows past our planet as if traveling in nearly straight lines, or “radially,” like spokes on a bicycle wheel, from the Sun in all directions. But the Sun rotates as it releases the solar wind, and before it is released, the solar wind is expected to synchronize with the Sun’s rotation.
“The solar wind leaves the coronal hole in a smooth flow. But also, there are jets; the moment everything reaches Earth, it is mixed, ”explains Bale.
Parker also looked at the first direct evidence that dust begins to thin out about eleven billion kilometers from the Sun , an effect that has been theorized for nearly a century, but was until now impossible to measure.
Strange explosions of energetic particles
Finally, the Parker probe’s Integrated Scientific Investigation of the Sun (ISʘIS) energetic particle instruments have measured a rare type of particle explosion with a particularly high proportion of heavier elements, suggesting that both types of events may be more common than scientists thought.
Solar energetic particle events are important as they can arise suddenly and cause potentially damaging weather conditions near Earth for astronauts.
What is the Parker probe data for?
As explained in a NASA statement, the information Parker has discovered about how the Sun constantly expels matter and energy can help scientists predict space weather around our planet; furthermore, it helps to understand the process by which stars are created and evolve.
And, more specifically, this information will be vital to protect astronauts and technology in space, for example, for the imminent mission to the Artemis Moon, which will be launched in 2024, and which will send the next man and the first woman to our satelite.
The results will be discussed and compared in talks at the next meeting of the American Geophysical Union in San Francisco that begins December 8.
During his initial flybys, Parker studied the Sun from a closer distance from the Sun than Mercury. And it will get even closer on future flights.
