The Solar Wind

Space isn't empty, especially not in the Solar System, it is filled with a stream of particles given off by the sun called the Solar Wind. Well, when I say "not empty", I mean "almost not empty" . If you take an imaginary cube of space, one centimeter on all sides, it will be filled with about 10 particles of solar wind. On the Earth, if you were to fill it with the atmosphere you are breathing now, it would be filled with 20,000,000,000,000,000,000 particles of air. The solar wind is made up of mostly protons and electrons (which are tiny bits that make up atoms), and travels very fast.

A bullet from a high powered hunting rifle travels at about 1 kilometer per second. The Space Shuttle orbits the Earth at about 8 kilometers per second. The Solar Wind travels anywhere between 200 to 700 kilometers per second!

Plasma Analysers

So how do you actually measure this near vacuum? That's what my Ph.D project is all about. I am designing instruments called "Top Hat Hemispherical Analysers". They are scientific experiments that measure not only how many solar wind electrons there are, but also how fast they are moving. From this, scientists can find out all sorts of important information and learn about space plasma. My group has worked on Plasma Analysers from five un-manned robotic missions that are in space right now.

  • Cluster - Four Spacecraft flying in formation around the Earth, studying how the solar wind interacts with Earth's magnetic field
  • Double Star - China's very first dedicated scientific mission to the Earth's Magnetosphere
  • Cassini - A spacecraft the size of a bus in orbit around Saturn
  • Mars Express - Europe's first mission to the red planet
  • Venus Express - The sister-ship of Mars Express. You can probably guess which planet it is in orbit around.

 
What is your project on?

I am working on designing the next generation of Plasma Detector, as well as trying to calibrate the instrument aboard Venus Express.