Posted on 26 January 2012
Magnetic fields exist throughout galactic and intergalactic space. What is puzzling is how they were originally created and how they became so strong.
The experiment shows that physicists and astrophysicists when teamed together and given access to a high-power laser can answer questions that span billions of years
Dr Nigel Woolsey
The team, which included University of York plasma physicists, used a high-power laser to explode a rod of carbon, similar to pencil lead, in helium gas. The explosion was designed to mimic the cauldron of plasma – an ionized gas containing free electrons and positive ions – out of which the first galaxies formed.
The scientists found that within a microsecond of the explosion strong electron currents and magnetic fields formed around a shock wave. Astrophysicists took these results and scaled them through 22 orders-of-magnitude to find that their measurements matched the ‘magnetic seeds’ predicted by theoretical studies of galaxy formation.
A report of the research, which received funding from the European Community’s Seventh Framework Programme, is published in this week’s Nature.
Dr Nigel Woolsey and Dr Chris Gregory from the York Plasma Institute were involved in the experiment from the proposal and preparation stages through to the experimental work and analysis.
The York Plasma Institute, a collaboration between the University of York's Department of Physics and the Engineering and Physical Sciences Research Council (EPSRC), is one of leaders in Europe in laboratory astrophysics.
Dr Woolsey, who has worked to establish the use of powerful lasers for astrophysics research since early 2000, said: “Laboratory astrophysics is a fairly new approach which involves conducting experiments in a laboratory to address questions astronomers and astrophysicists have about the Universe.
“The experiment shows that physicists and astrophysicists when teamed together and given access to a high-power laser can answer questions that span billions of years. This opens the physics of early Universe to an exciting new approach, allowing the exploration of the cosmos here on Earth in a laser laboratory.”
The results closely match theories which predict that tiny magnetic fields – 'magnetic seeds' – precede the formation of galaxies. These fields can be amplified by turbulent motions and can strongly affect the evolution of the galactic medium from its early stages.
The experiments, which were led by Oxford University, were conducted at the Laboratoire pour l’Utilisation de Lasers Intenses laser facility near Paris over a three-week period.