An international team, which includes researchers from California State University Northridge, has devised a high-precision method of examining magnetic fields in the Sun’s atmosphere, representing a significant leap forward in the investigation of solar flares and potentially catastrophic ‘space weather’.
Solar flares are massive explosions of energy in the Sun’s atmosphere. Experts have warned that even a single ‘monster’ solar flare could cause up to $2 trillion worth of damage on Earth, including the loss of satellites and electricity grids. It also poses potential dangers to human life and health.
The technique pioneered by the research team, published today in the journal Nature Physics, will allow changes in the Sun’s magnetic fields, which drive the initiation of solar flares, to be monitored up to ten times faster than previous methods, allowing for greater advanced warning of potentially devastating space storms.
The research team members, who span universities in Europe, the Asia-Pacific and the USA, harnessed data from both NASA’s premier space-based telescope (the Solar Dynamics Observatory) and the ROSA (Rapid Oscillations in the Solar Atmosphere) multi-camera system at the National Solar Observatory in Sunspot, NM.
Lead researcher Dr. David Jess from Queen’s University Belfast said: “Continual outbursts from our Sun, in the form of solar flares and associated space weather, represent the potentially destructive nature of our nearest star. Our new techniques demonstrate a novel way of probing the Sun’s outermost magnetic fields, providing scientists worldwide with a new approach to examine, and ultimately understand, the precursors responsible for destructive space weather.” Prof. Damian Christian of California State University Northridge, also a key member of the research team, adds, “Understanding the behavior of our Sun’s magnetic fields provides us with crucial information surrounding the immense energy it possesses, and we are very excited by the potential of our new technique to better predict solar flares.”
This breakthrough will help facilitate future research, including the continual measurement of magnetic fields in the outer regions of the Sun’s atmosphere, which is one of the key goals of the new $300 million Daniel K Inouye Solar Telescope (DKIST), which will be the largest solar telescope in the world when construction is finished in 2019 on the Pacific island of Maui. Researchers from this international team are also heavily involved with the DKIST project.
The paper, entitled ‘Solar Coronal Magnetic Fields Derived Using Seismology Techniques Applied to Omnipresent Sunspot Waves’, can be read at:https://www.nature.com/articles/doi:10.1038/nphys3544
Specific research results include:
(1) The datasets used provided unprecedented images of all layers of the Sun’s tenuous atmosphere, allowing the team to piece the jigsaw puzzle together of how magnetic fields permeate the dynamic atmosphere. Images captured by NASA’s Solar Dynamics Observatory and STEREO spacecrafts provided million-degree vantage points of how these magnetic fields stretch far out into the Sun’s corona (the region of the Sun’s atmosphere visible during total solar eclipses)
(2) Waves propagated along magnetic fields, similar to how sound waves travel through the air on Earth. The speed at which these waves can travel is governed by the characteristics of the Sun’s atmosphere, including its temperature and the strength of its magnetic field. The waves were found to propagate with speeds approaching half a million (500,000) mph, and when coupled with temperatures of around 1,000,000 degrees in the Sun’s outer atmosphere, the researchers were able to determine the magnetic field strengths to a high degree of precision
(3) The strength of the magnetic fields decreases by a factor of 100 as they travel from the surface of the Sun out into the tenuous, hot corona. While the magnetic fields have decreased in strength, they still possess immense energy that can twist and shear, ultimately releasing huge blasts towards Earth in the form of solar flares. The team’s methods provide a much faster way of examining magnetic field changes in the lead up to solar flares, which can ultimately be used to provide advanced warning against such violent space weather