Anthony Yeates博士はthe Department of Mathematical Sciencesに在籍し、ダラム大学がダンディー大学と立ち上げた総額£818,000のコンソーチウムのうち、£68,000の研究資金を得て、研究に挑みます。
The aim of the work is to understand the basic physical processes that go on in plasmas on the sun and throughout the Universe. In this project they will particularly focus on the solar corona, the outer atmosphere of the sun. Magnetic loops in the solar corona, solar flares and coronal mass ejections, are among the phenomena that scientists still cannot fully explain.
Plasma, an ionised gas, clings to magnetic fields in the sun’s atmosphere. This means that the magnetic loops in the atmosphere can be seen by high-powered telescopes due to the radiating plasma. The images these telescopes capture show that the plasma on the magnetic loops has temperatures of more than a million degrees, far higher than that of the 5800C surface of the sun.
The Magnetohydrodynamics group within the University of Dundee’s Division of Mathematics has received £765,000 from the Science and Technology Facilities Council for the three-year ‘Complex Magnetic Fields: An Enigma of Solar Plasmas’ study.
Before taking up his post at Durham University, Dr Yeates worked with the Dundee team as a post-doc researcher. His share of the STFC grant will fund a significant proportion of his research time at Durham for the next three years and he will continue to work with his former colleagues on the project. He is taking the lead for one particular project: ‘Quantifying reconnection in the global solar corona’.
He said: “The latest satellite observations reveal these magnetic loops to be more dynamic than we imagined before. They are continuously changing and evolving.
“By measuring these changes, we aim to understand why the loops are so hot, and how they can suddenly explode, leading to solar flares and even coronal mass ejections.”
Coronal mass ejections are explosive events in which billions of tonnes of solar plasma are thrown into space. Depending on the direction in which it is thrown, a mass ejection may be on a collision course with the Earth as it moves through interplanetary space.
It is when such a mass crashes into the Earth’s magnetic field that the Northern and Southern Lights occur. Less welcomingly, it can also cause problems for spacecraft, satellites, and high-flying airplanes. Blackouts in power distribution systems and corrosion of oil pipelines are other potential side-effects of what is known as “space weather”.
Finding out why the magnetic loops are so much hotter than the solar surface is another key aim of the work, according to Professor Gunnar Hornig, who is part of the Dundee University group.
“It is really surprising that with distance from the core of the sun the temperature drops until it’s relatively cool at the surface but then increases dramatically such that coronal loops have multi-million degree temperatures,” said Professor Hornig.
“We don’t know why these loops are so hot, why they occur in the way and number they do, and this is what we endeavour to discover.”
He said that understanding how the sun worked, and the structures we saw on it, would broaden our knowledge of the whole solar system, including our planet. It might also help to resolve some of the challenges that scientists have battled with for decades, or even centuries, and prove to have practical benefits for everyday life.
He added: “Another aspect to the research is to try and understand the behaviour of magnetised plasmas in general. This is of interest, not only for astrophysics, but also fusion physics. In fusion, we try to capture the same process that heats the sun on earth in machines that encase plasma in a magnetic field and they try to make fusion.
“This is a long term effort which started about 50 years ago or so. The same type of problems that have so far prevented people from building a working fusion reactor are also affecting plasma on the sun. So, by studying this, we also improve our understanding of how fusion plasmas work.”