Plasma: A View From Space

Some readers of Physics World might be surprised to learn that 99% of the visible universe is made of plasma. Highly ionized gas containing roughly equal numbers of electrons and positive ions, plasma exists in a very dilute form in interstellar space, as well as in stellar atmospheres and in more exotic objects such as neutron stars. Then there are the tiny pockets of man-made plasma found inside fusion reactors, which it is hoped might one day provide us with a plentiful and clean supply of energy.