◎ Science and Technology Daily intern reporter Zhang Jiaxin
Comprehensive foreign media latest news, the National Aeronautics and Space Administration (NASA) Scientific Mission Council deputy director Thomas Zubchin announced at the 2021 American Geophysical Union Autumn Meeting held on the 14th that three years after the launch of the "Parker" solar probe, on April 28 this year, at 9:33 EASTERN time in the United States reached the outermost layer of the solar atmosphere (corona), and stayed there for 5 hours, becoming the first spacecraft to "contact the sun". The results were also published in the Physical Review Letters.
Artist's vision of the Parker solar probe approaching the sun. Source: Physicists Organization Network
This mission was led by the Applied Physics Laboratory at Johns Hopkins University in the United States. The researchers say the Parker Solar Probe crossed the corona on its eighth approach to the sun in April. It took them months to recover the data, and then another few months to confirm. According to NASA, this is a milestone in the study of solar science, not only giving people a deeper understanding of the evolution of the sun and its impact on the solar system, but also helping people learn more about other stars in the universe.
In 2018, NASA launched the Parker Solar Probe, with the ultimate goal of reaching the solar corona and achieving the first close "contact" of the star.
The outer edge of the Sun begins at the Alfin Pro interface, below which the Sun's gravity and magnetism directly control the solar wind. In April, Parker stayed below the Alfin Pro interface for 5 hours, in direct contact with the sun's plasma. Beneath this plane, the pressure and energy of the Sun's magnetic field is stronger than the pressure and energy of the particles.
The probe made the first direct observations of material in the sun's atmosphere, revealing findings about the sun.
The Parker solar probe reaches the sun's outer atmosphere (corona). Source: CNN website
The Sun's corona is much hotter than its actual surface. The maximum temperature of the corona is 1 million Kelvin (1.8 million degrees Fahrenheit), while the surface temperature is about 6000 Kelvin (10340 degrees Fahrenheit).
Parker was in and out of the corona several times, which helped the researchers understand that the Alfin Pro interface is not a smooth circle around the sun, but a jagged, uneven, spike and valley floor, an area where many scientists believe that the sun's magnetic field reversal occurs. Parker arrived here about 8 million miles (about 13 million kilometers) from the center of the sun.
The researchers noticed that the amplitude of the Alphen Pro interface depression was much lower than the amplitude of its bulge. This discovery could mean that no reversal of the solar magnetic field forms within the corona. Alternatively, the magnetic reconnection rate of the Sun's lower atmosphere may cause fewer reversals.
During its overflight of the corona, Parker passes through an area known as the pseudocolic flow as it travels 6.5 million miles (about 10.46 million kilometers) from the sun's surface, a large magnetic structure that bulges on the sun's surface and can be observed from Earth during a solar eclipse. The data suggest that the largest and farthest undulations of the Alfen Pro interface are generated by pseudo-coronal streams. It is unclear why the pseudo-coronal stream pushes the Alfin Pro interface away from the Sun.
Artist's vision of the Parker solar probe approaching the sun. Image source: National Aeronautics and Space Administration (NASA)
The scientists also observed that the sun's magnetic field pulls the solar wind in the same direction as it rotates at great distances, not just at close range, which increases the speed of the solar wind as it moves away from the sun.
The probe also recorded some evidence of potential energy boosts inside the corona, which could affect heating and dissipation.
The Parker solar probe may reportedly fly over the corona again in its next flyby in January. Before the mission is completed, it will approach the sun 21 times in seven years. In 2024, the probe will operate at a surface range of 3.9 million miles from the sun, which is closer to the sun than the closest planet to the sun, Mercury.
The researchers say that as the Parker solar probe flies into the corona, people will have a deeper understanding of the inner workings of this mysterious region.
Source: Science and Technology Daily
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