The Sun likes to remind us that the Earth is just one part of a connected system. There are ultraviolet rays that can burn our skin and eyes and even cause extinction. That light can disappear completely during an eclipse, throwing us a winding, tangled array of solar flares and plasma-filled coronal mass ejections. Despite our cosmic connection to the Sun, there are still many scientific mysteries to be solved about this important star, especially its magnetic field.
“The sun is not just in a void with which we are not connected.” sarah gibsonsays a solar physicist at the National Science Foundation’s National Center for Atmospheric Research (NCAR) in Colorado. popular science. “The aurora actually shows us that direct connection. We are connected to what’s happening on the sun through light and ultimately through magnetic fields.”
For the first time, scientists have measured the sun’s coronal magnetic field almost every day. This important spot has only been observed in irregular increments, but this new observation provides a more dynamic view of this solar region. With it, we could learn more about the causes of intense solar storms that can affect basic technology on Earth. For more information on the survey results, please visit The study was published in the journal Oct. 3 science.
[Related: Why is the sun’s corona 200 times hotter than its surface?]
What is the solar magnetic field?
The solar magnetic field is the main cause of solar storms and solar flares. As society becomes more dependent on technology, this space weather poses a threat to power grids, communications systems, and space technologies such as GPS and satellites.
“We need to understand space weather. We need to predict space weather. The big gap in our knowledge is that we don’t have measurements of the sun’s magnetic field in its atmosphere, or corona. ” says Gibson, co-author of the new study. “That’s the part you see during a solar eclipse. The magnetic field controls the shape of the atmosphere and controls where the plasma, or ‘matter’, is located. ”
Measuring the magnetism in this region typically requires large, expensive equipment that can only study small parts of the corona. However, combining coronal seismology and new observation methods has enabled researchers to generate a consistent and comprehensive view of the global corona’s magnetic field.
“Global mapping of the coronal magnetic field is a major missing piece in solar research.” Yang Jihaoa study co-author at Peking University in China and a postdoctoral fellow at NCAR; stated in a statement. “This research helps fill a critical gap in our understanding of coronal magnetic fields, the source of energy for storms that can impact Earth.”
A tale of two instruments
Scientists have been able to routinely measure the magnetic field on the sun’s surface, called the photosphere. Measuring the much dimmer coronal magnetic field is more difficult, limiting a deeper understanding of the three-dimensional structure of the corona and the evolution of the magnetic field.
Large telescopes such as NSF’s Daniel K. Inouye Solar Telescope (DKIST) can measure the three-dimensional coronal magnetic field to depth. With a massive 13-foot diameter aperture, DKIST is the world’s largest solar telescope. We recently demonstrated the ability to make detailed observations of the coronal magnetic field. However, DKIST cannot map the sun all at once.
[Related: See hot plasma bubble on the sun’s surface in powerful closeup images.]
To obtain a more comprehensive mapping, the team turned to: Upgraded coronal multichannel polarimeter (UCoMP). UCoMP is well suited to provide scientists with a more complete picture of the coronal magnetic field, but it has lower resolution and is provided in a two-dimensional projection.
Like a solar eclipse, UCoMP can block out part of the sun. A disk called a coronagraph allows scientists to measure the sun’s atmosphere. UCoMP’s aperture is much smaller than DKIST, at about 7 inches, but it provides a wider field of view, allowing scientists to study the entire Sun on most days.
team applied a method called coronal seismology. Track magnetohydrodynamic (MHD) shear waves in UCoMP data. From the MHD waves, we were able to create a two-dimensional map of the strength and direction of the coronal magnetic field.
During the UCoMP study, the team produced the following artifacts: 114 magnetic field maps Approximately once every other day from February to October 2022.
“We are entering a new era of solar physics research where coronal magnetic fields can be routinely measured,” Yang said.
Using DKIST and UCoMP measurements together provides a more complete view of the coronal magnetic field.
Get photos
This research method also first measurement of the coronal magnetic field of polar regions of the sun. These poles have never been directly observed because the curve of the Sun near them makes them beyond view from Earth.
Although the research team did not directly observe the sun’s poles, they were the first to measure the magnetic field emanating from them. The improved data quality provided by UCoMP and the Sun’s proximity to solar maximum enabled us to obtain the first measurements of its kind. The generally weak radiation from the polar regions has become much stronger, making it easier to obtain results for the coronal magnetic field in the polar regions.
[Related: Rare quadruple solar flare event captured by NASA.]
The team plans to continue studying magnetic fields, capturing them in three dimensions. Obtaining a 3D view is especially important for understanding how the corona is energized in the lead up to a solar explosion.
“This is the first time we’ve observed the entire Earth’s coronal magnetic field, but it still looks like a 2D version of a 3D,” Gibson says.
Ultimately, measuring all the three-dimensional twists behind solar eruptions will require a combination of large telescopes and a global field of view. proposed Coronal Solar Magnetic Observatory (COSMO) is a solar refractor telescope approximately 5 feet in diameter currently in final design consideration.