ESA Moves Forward on New Electric Engine

museumpeace writes to tell us the ESA is reporting that they have confirmed the principle behind a new space thruster. Plasma Double Layers, first discovered by Australian researchers Christine Charles and Rod Boswell, may help to develop a new electric engine that gives more thrust than traditional engines while still maintaining efficiency. From the article: "In essence, a plasma double layer is the electrostatic equivalent of a waterfall. Just as water molecules pick up energy as they fall between the two different heights, so electrically charged particles pick up energy as they travel through the layers of different electrical properties."

Comments

Basic kinetics...

[sac13]

In essence, a plasma double layer is the electrostatic equivalent of a waterfall. Just as water molecules pick up energy as they fall between the two different heights...

Water molecules do not pick up energy as they fall. There potential energy is simply converted into kinetic energy. However, they had the energy all along in the form of potential energy.

Re:Basic kinetics...

[iabervon]

It's not really meaningful to say that the water molecules had potential energy; the system had potential energy as a result of the water molecules being away from the ground, but falling causes that potential energy to become localized in the water. Of course, there's not much else that can happen to gravitational potential energy in the reference frame of the planet, but in the case of charged particles in electric fields, that potential can come out in lots of ways: like moving the particles, moving the device, or causing current to flow in the device. It doesn't make sense to say that the potential energy is in a particular part of the system, when it can become kinetic energy in any of a number of parts depending on how it is released.