Ion wind

Under ion wind is defined as a directed flow of ions, ie a type of ionizing radiation. It is generated by a gas discharge that (mostly pointed shape, which brings a very strong inhomogeneity of the electric field with it ) from a position of positive high voltage electrode emanates. The ionization takes place by removal of electrons. The thus generated positive ions are then separated from the electrode ( anode) path along the field gradient. At an opposite, negatively charged electrode (cathode) of any shape, the ions in turn take on electrons.

The direction of motion of the ions as they are positively charged, the conventional current direction " from plus to minus ." The direction of the electron flow, for example, a lead wire would be reversed.

Historical

Gas discharges at low pressure were observed in 1897 by Joseph John Thomson experimentally in a so-called cathode ray tube. The later recognized as a positive ion radiation that caused a mica publication and of was called " canal rays ".

Furthermore, it was also observed a cathode glow, a light-emitting phenomenon, which is caused by the high kinetic energy of the gas ions from the cathode triggered secondary electrons. The electrons are accelerated towards the anode and called cathode rays.

Technical Applications

Ion wind at atmospheric pressure in ordinary air, ie oxygen, and nitrogen, produces a blue-violet glow discharge with ultraviolet ( UV) portions. The ionization and UV radiation produce oxygen radicals, which attach themselves to molecular oxygen, thus the aggressive gas ozone is formed. This effect is used in devices, often called ozonizer, ozone for air purification (especially for odor neutralization) or for disinfecting water use.

Due to the ion wind and normal wind can be generated in terms of air flow. It can be constructed fan who can get along and therefore operate almost silently with no moving parts. It will reach flow velocities are s 2.5 m / above the speed mechanical fan.

In space technology, ion thrusters with inert gases are used as control thrusters.