Source: phys. org
Astronomers are one step closer to understanding one of solar energy’s most enduring mysteries, after obtaining unprecedented data from the Sun’s magnetic field.
Pioneering data collected by the US National Science Foundation’s Daniel K. Inouye Solar Telescope (DKIST) in Hawaii, the world’s most powerful solar telescope, has provided the most detailed images yet of the magnetic field of the Sun’s so-called “quiet” surface.
An international team of scientists, including researchers from the University of Sheffield, believe the data has implications for how energy transfer between the sun’s layers is modeled. The study was published in the Astrophysical Journal Letters.
This may help explain one of the biggest mysteries in astrophysics: why the Sun’s outer layer (the corona) is hundreds of times hotter than the surface (the photosphere), even though the opposite is expected.
Professor Robertus Erdely, one of the senior researchers involved in the School of Mathematics and Statistics at the University of Sheffield, said: “The observations have revealed and confirmed the existence of a zigzag topology of the magnetic field in the lower atmosphere of the sun, which is often called the chromosphere.
Knowledge of magnetic field geometry is essential to understanding the various energetic phenomena that drive plasma dynamics in the solar atmosphere.
“This includes much-needed magnetic behavior that may ultimately be responsible for energizing solar plasma to temperatures of millions of Kelvin,” Erdely added. “These magnetic fields are also thought to trigger the largest and most powerful explosions in our entire solar system, the coronal mass ejections (CME).” .
The Daniel K. Inouye Solar Telescope was able to detect a new and complex snake-like pattern of energy in the magnetic field.
In the past, much of the research on thermal differences between the corona and the photosphere has focused on “sunspots” (very large, highly magnetic and active regions, often comparable in size to Earth) that can act as energy conduits between the Sun’s outer layers. .
Aside from sunspots, the so-called “quiet sun” is covered in convection cells known as “granules”, which are typically the size of France, and contain much weaker but more dynamic magnetic fields that may hold the secrets to balancing the energy budget of the chromosphere.
Most observational reports in the past decade have found that magnetic fields are organized into small rings in the quiet photosphere. Using the Daniel K. Inouye Solar Telescope, scientists have discovered something unexpected: they have found the first evidence of a more complex pattern consistent with a snake-like variation in magnetic direction.
Professor Michael Mathioudakis, co-author of the research and director of the Agricultural Research Center at Queen’s University, said: “The more complex the small differences in the direction of the magnetic field, the more plausible it is for energy to be released through a process we call magnetic reconnection – when two magnetic fields pointing in opposite directions interact.” “They release energy that warms the atmosphere. We have used the world’s most powerful solar optical telescope to reveal the most complex magnetic field trends ever seen on the smallest scales. This brings us closer to understanding one of the biggest mysteries in solar research.”
Professor Erdely added: “Thanks to this research, we may be one step closer to understanding the Sun, our life-giving star.”