Science //

Sydney University harnesses the sun’s energy

Hushed away in their labs, our resident physicists are up to something, investigates Darcy Gray.

The Sun

When asked to conjure up a mental image of renewable energy sources, many people will picture solar panels sitting static on rooftops, or wind turbines turning lazily in the wind.

However the Plasma Physics group at the University of Sydney (occupying labs merely 160 metres from Manning House) imagines using one of the most energetic processes in existence, the very process which powers our own Sun.

Nuclear fusion

Nuclear fusion occurs at huge temperatures, in the range of millions of degrees Celsius, naturally only achieved at the centre of the sun, and combines the lightest element on earth, Hydrogen, into Helium (the second lightest). In this process some mass (m) of the Hydrogen is lost, converted directly into energy (E). Many of us will recognise the equation, E=MC2, which governs this conversion.

As C2 is approximately ninety quadrillion (m2s-2), even a small amount of mass change results in phenomenal amounts of energy. On top of this enormous energy output for the amount of fuel, fusion creates none of the dreaded radioactive waste which typical nuclear (fission) reactors produce – the only side effect of its waste is a slightly higher voice.

So why are the fantastic advantages of fusion technology over, say, solar or hydro power generation, not a focus of copious amounts of government funding and public advocacy? Well the technology is still in its infancy; with the first reactor demonstrating power generation ability (the International Thermonuclear Experimental Reactor, or ITER) in the pipeline to be online in France within ten years at an estimated construction cost of 13 billion euros. The first commercial reactor, DEMO, is to follow some time later.

This long development process is primarily caused by the need for a huge device (generally weighing thousands of tonnes), known as a Tokamak, which confines the extremely high temperature plasma with magnetic fields while fusion takes place.

This is where Sydney’s Plasma Physics group steps in. After Sydney’s Tokamak went offline in the late 90s this group has been pursuing an alternative form of fusion reactor, an inertial electrostatic confinement reactor, which is small and simple enough to be built in a home garage (and it has been!). This version of the reactor, initially invented by Philo Farnsworth (inventor of the television), uses electric fields to confine the high energy plasma long enough for fusion to take place.

This version of the fusion reactor is very promising; with the Sydney team one of the few groups in the world pursuing this area, another notably being the fairly secretive research performed by the US Navy. This military investment stems from the potential to miniaturise the reactor, which could be used in, amongst other things, a submarine.

Matthew Carr, a PhD student on the project, is convinced of the technologies’ potential, stating it may be what drives future generations of space craft as the deuterium fuel required is abundant on the surface layers of the moon.

“Some of the estimates for our machines are not very impressive. But it is the first machine, the first design,” he says.

If you take only one thing from this article let it be this: we have a tiny replica of the sun twinkling in our own university.

Vice Chancellor Michael Spence.

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