Ion wind, ionic wind, coronal wind or electric wind are expressions formerly used to describe the resulting localized neutral flow induced by electrostatic forces linked to Corona discharge arising at the tips of some sharp conductors (such as points or blades) submitted to high-voltages relative to ground. Modern implementations belong to the family of Electrohydrodynamic (EHD) devices.
Ion wind production machines can be now considered as Electrohydrodynamic (EHD) pumps.
Francis Hauksbee, curator of instruments for the Royal Society of London, made the earliest report of electric wind in 1709. Myron Robinson completed an extensive bibliography and literature review during the 1950s resurgence of interest in the phenomena.
Electric charges on conductors reside entirely on their external surface (see Faraday cage), and tend to concentrate more around sharp points and edges than on flat surfaces. This means that the electric field generated by charges on a sharp conductive point is much stronger than the field generated by the same charge residing on a large smooth spherical conductive shell. When this electric field strength exceeds what is known as the corona discharge inception voltage (CIV) gradient, it ionizes the air about the tip, and a small faint purple jet of plasma can be seen in the dark on the conductive tip. Ionization of the nearby air molecules result in generation of ionized air molecules having the same polarity as that of the charged tip. Subsequently, the tip repels the like-charged ion cloud, and the ion cloud immediately expands due to the repulsion between the ions themselves. This repulsion of ions creates an electric "wind" that emanates from the tip, which is usually accompanied by a hissing noise due to the change in air pressure at the tip. An opposite force act on the tip that may recoil if not tighten to ground.
- Ion thruster
- Ionocraft (AKA Lifter)
- Hall effect thruster
- Magnetoplasmadynamic thruster
- Spacecraft propulsion
- Field Emission Electric Propulsion
- Pulsed inductive thruster
- Magnetohydrodynamic drive
- Air ioniser
- List of plasma (physics) articles
- Robinson, M. (1962, May). History of the electric wind. American Journal of Physics, 30(5), 366-372.
- Robinson, M. (1960, June 8). Movement of Air in the Electric Wind of the Corona Discharge. (AD0262830)