New concepts of all-electric propulsion by ionic wind – PROPULS-ION

Innovations to improve aircraft propulsion performance have been relatively incremental over the past 30 years, but they are necessary from an environmental and energy point of view, due to the constant increase in air traffic. They are mainly concerned with improving engine performance or aerodynamic characteristics. In this context, electric propulsion is a promising field of research because it reduces the carbon impact.
A new path has opened up in recent years with the idea of using the ionic wind as a propulsive mechanism. In this case, the propulsion is entirely electric since the initial energy is electric, so does the physical phenomena causing the thrust. Indeed, the ionic wind is due to the acceleration of electrical charges by an electric field, resulting in a momentum transfer to the neutral molecules of the air, from collisions. Then an “ionic wind" is produced. More simply, the electroaerodynamic body force (EAD) at the origin of the thrust corresponds to the sum of every Coulomb force acting on each electrical charge. These charges are created by a "corona discharge", a cold plasma that occurs in air near a very small diameter tip or wire to which a high voltage is applied.
There is a significant challenge to explore this new paradigm of "all-electric" aircraft propulsion. Indeed, the team of Professor Barrett (MIT, USA) succeeded in flying a 2.4 kg drone with a wingspan of 5 meters with this type of propulsion. The results of this work were published in Nature in November 2018. Since then, Professor Barrett has been invited to numerous TV shows and international conferences. It therefore seems obvious that a significant number of American research teams will start working on this subject, funded by their government. Therefore, it is important to develop research in France in this field because it represents a strategic challenge.
The first scientific publication on the possibility of using ionic wind as a propulsion mechanism dates back to 1967 [Christopher & Moller] and only about ten articles have been published since then. Originally, American researchers thought they could use this propulsion method for ballons flying in our atmosphere, up to about 30 kilometers above sea level. It is still conceivable that electroaerodynamic propulsion can be applied to this type of atmospheric ballons, for surveillance or transmission applications. Moreover we can also imagine that the all-electric aircraft of the future could use EAD propulsion.
EAD propulsion has many advantages. First of all, it is silent and thermally stealthy. In addition, it consists only of simple electrodes (no moving parts), which makes it very robust and deployable over a large surface because the electrodes can be simple wires or rigid rods of very small diameter. It is also important to mention the possibility of interfacing this propulsion with solar panels that can be deployed at high altitude, which would provide the electrical energy required for propulsion.
If successful, the impact of this research will be very significant, since it offers a totally innovative propulsion system that has only been the subject of a few articles in scientific journals to date.