Introduction
Back in 2021 I built 2 prototypes of magnetohydrodynamic drives. Although it sounds fake it is quite real. According to the Alexandria Engineering Journal “The basic principle of MHD is straightforward; a unidirectional current is established through an electrically conducting fluid such as seawater. Then, a high intensity magnetic field perpendicular to the current is imposed through the fluid. This combination of orthogonal magnetic field, electric field, and a relative motion of ions results in a Lorentz force with direction defined by the cross product of current and magnetic field vectors. If the device containing the electromagnet and the enclosure is fixed, the fluid is essentially pumped. However, if the device is free or has minimal resistance to motion, it will recoil according to Newton’s second law of motion. In this case, the device is referred to as pump-jet or thruster.”(Al-Habahbeh, 2016) while this sounds super complicated it really is quite simple what this paper is saying is as follows: an electrical current is conducted though an anode into a conductive fluid (like salt water) and received by a cathode creating an electric field. then a magnetic field is created perpendicular to the electric field using either an electromagnet (like the ones that drive speakers) or a permeant magnet (like the ones you put on your fridge but much stronger). The interaction between the two fields and the conductive liquid is the liquid gets “pushed” through the crossed fields. This property can be used in a number of ways but I was most interested in propulsion.
The Design
I aimed for simplicity over all else. My anode and cathode were folded up tinfoil, and the magnets were Neodymium Bar Magnets. I used 9V batteries wired in series to power it and that’s about it!
The End Result
Sources:
O.M. Al-Habahbeh, M. Al-Saqqa, M. Safi, T. Abo Khater,
Review of magnetohydrodynamic pump applications,
Alexandria Engineering Journal,
Volume 55, Issue 2,
2016,
Justin Willock 