How does a Magnetohydrodynamic drive work?

Question

Henry Asbill · Accepted Answer

Magneto Hydrodynamic drives work by passing an electric current through a fluid in the presence of a magnetic field.

Research is being done on magnetohydrodynamic drives for spacecraft and oceangoing ships alike. In a ship, sea water is circulated through a tube that runs the length of the vessel. The salt water is electrically conductive, and an electric current is passed through it. The water is subjected to a strong magnetic field that is perpendicular to the electric current, combining to exert force on the water that propels it out of the ship's back. Magneto hydrodynamic drives have the advantage of being significantly quieter due to the lack of propellers or other moving parts. Magneto hydrodynamic drives have a drawback in that strong magnetic fields would necessitate superconducting magnets, which require costly and large cooling systems. Instead, they rely on a generator to produce the electric current, which must be driven by some sort of engine or reactor. Plasma would take the place of sea water as the conducting propellant in a spacecraft. Technological advancements are necessary to make Magneto Hydrodynamic drives more cost-effective because they are currently slower and more expensive than conventional propulsion systems.

Ian Ashcroft · Answer

undefined A magnetohydrodynamic drive is based on the interaction of electrically conductive seawater with a magnetic field, producing a propulsive force, which is used to ionize and accelerate seawater in order to generate thrust without the need for conventional propellers.

Parker Albertson · Answer

undefined A Magnetohydrodynamic (MHD) drive works by using magnetic fields to accelerate and propel a conductive fluid, typically plasma, in order to generate thrust. This technology relies on the principles of electromagnetism and fluid dynamics. Here's a simplified explanation of how it works:

1. **Plasma Generation**: A conductive fluid, often ionized gas or plasma, is produced. This plasma can conduct electricity and interact with magnetic fields.

2. **Magnetic Field Generation**: Powerful magnets or electromagnets are used to create a magnetic field around the plasma.

3. **Lorentz Force**: When an electrically conductive fluid moves through a magnetic field, it experiences a force known as the Lorentz force. This force acts perpendicular to both the direction of the current (in this case, the flow of plasma) and the magnetic field.

4. **Thrust Generation**: By applying an electric current to the plasma, or by inducing currents through other means, the plasma is propelled by the Lorentz force. As the plasma moves through the magnetic field, it experiences a force that propels it in a specific direction, generating thrust.

5. **Propulsion**: The thrust generated by the interaction of the plasma with the magnetic field propels the spacecraft or vehicle forward. By controlling the strength and direction of the magnetic field, as well as the flow of plasma, the direction and magnitude of thrust can be controlled, allowing for maneuverability.

Overall, Magnetohydrodynamic drives offer a potentially efficient and fuel-free method of propulsion for spacecraft and other vehicles operating in environments where traditional propulsion methods may not be suitable or efficient. However, practical implementation of MHD drives is still in the experimental stage and faces various technical challenges.