Planes of the future might not need any moving control surfaces at all. The trouble with fashion is that it is based on the whims of those who buy into it, and the amazing claims made for plasmas have the insidious smell of Cold War hype about them. The story begins in the late 1970s, when Anatoly Klimov embarked on an unremarkable series of experiments at the Moscow Radio-Technological Institute, one of the Soviet Union's most secretive laboratories. His goal was to understand how shock waves behave in ionised gases, a topic of real interest to plasma physicists, for whom the phenomenon seemed rich in possibilities. Hot and loud But shock waves are also of interest to the aerodynamicists who design re-entry vehicles and hypersonic aircraft, for whom they are troublesome obstacles in the quest for speed.
Shock waves slow vehicles down, cause terrific heating and create sonic booms.
For these researchers, any suggestion that they can be reduced or modified is manna from heaven. Which is why the work of Klimov and colleagues at the Ioffe Institute in St Petersburg was so interesting. One experiment by the Ioffe group involved firing a steel sphere the size of a walnut at 1 kilometre per second through a tube filled with argon gas at low pressure. Gas in a section of the tube was ionised to create a plasma, and the group filmed the shock wave around the sphere before and after it entered the plasma. To their surprise, they found that the difference was huge.