Astronomers find clues to decades-long coronal heating mystery
The observations help to answer a 70-year-old solar physics conundrum about the unexplained extreme temperature of the Sun's corona – known as the coronal heating problem.
Hahn and Savin analyzed data from the Extreme Ultraviolet Imaging Spectrometer onboard the Japanese satellite Hinode. They used observations of a polar coronal hole, a region of the Sun where the magnetic fields lines stretch from the solar surface far into interplanetary space. The findings were published on September 30th in the October 20th edition of The Astrophysical Journal.
To understand the coronal heating problem, imagine a flame coming out of an ice cube. A similar effect occurs on the surface of the Sun. Nuclear fusion in the center of the Sun heats the solar core to 15 million degrees. Moving away from this furnace, by the time one arrives at the surface of the Sun the gas has cooled to a relatively refreshing 6000 degrees. But the temperature of the gas in the corona, above the solar surface, soars back up to over one million degrees. What causes this unexpected temperature increase has puzzled scientists since 1939.
Two dominant theories exist to explain this mystery. One attributes the heating to the loops of magnetic field which stretch across the solar surface and can snap and release energy. Another ascribes the heating to waves emanating from below the solar surface, which carry magnetic energy and deposit it in the corona. Observations show both of these processes continually occur on the Sun. But until now scientists have been unable to determine if either one of these mechanisms releases sufficient energy to heat the corona to such high temperatures.
Hahn and Savin's recent observations show that magnetic waves are the answer. The advance opens up a realm of further questions; chief among them is what causes the waves to damp. Hahn and Savin are planning new observations to try to address this issue.
This research has been supported by the National Science Foundation Division of Atmospheric and Geospace Sciences through the Solar, Heliospheric and Interplanetary Environment program.
Scientific contacts:
Michael Hahn
Columbia University Astrophysics Laboratory
646-708-3461
Daniel Savin
Columbia University Astrophysics Laboratory
646-707-4937
The manuscript can be found at: http://arxiv.org/abs/1302.5403
Media Contact
More Information:
http://www.columbia.eduAll latest news from the category: Physics and Astronomy
This area deals with the fundamental laws and building blocks of nature and how they interact, the properties and the behavior of matter, and research into space and time and their structures.
innovations-report provides in-depth reports and articles on subjects such as astrophysics, laser technologies, nuclear, quantum, particle and solid-state physics, nanotechnologies, planetary research and findings (Mars, Venus) and developments related to the Hubble Telescope.
Newest articles
High-energy-density aqueous battery based on halogen multi-electron transfer
Traditional non-aqueous lithium-ion batteries have a high energy density, but their safety is compromised due to the flammable organic electrolytes they utilize. Aqueous batteries use water as the solvent for…
First-ever combined heart pump and pig kidney transplant
…gives new hope to patient with terminal illness. Surgeons at NYU Langone Health performed the first-ever combined mechanical heart pump and gene-edited pig kidney transplant surgery in a 54-year-old woman…
Biophysics: Testing how well biomarkers work
LMU researchers have developed a method to determine how reliably target proteins can be labeled using super-resolution fluorescence microscopy. Modern microscopy techniques make it possible to examine the inner workings…
