Plasma Magnetic sail

[KHambsch]

I think this propulsion concept fell between the cracks at the time the Phase I and II NIAC reports were released in I believe circa 2007. To start with, this is a type of sail which exploits the solar wind, is considered a drag device...like a sailboat in the wind. For this reason I'm not sure it can be called a propulsive device. That notwithstanding, I'll continue with the explanation and description of this super fast sail concept.
Falling through the cracks:
1) Both reports were release at the time that NIAC was no longer being funded by NASA (around 2007)...if memory serves.
2) The US and indeed most of the world was in the throws of the 2007-2009 financial crisis.
3) The concept very likely was confused with another concept developed by Winglee at the University of Washington....that concept being M2P2. The community questioned seriously the workablity of this (M2P2) inflating of a static dipolar magnetic field with an ionized gas.
4) Lastly, this concept should not be confused with the Zubrin Magsail, and/or the Janhunan electric sail.
The Plasma Magnet(ic sail) (PMsail) was developed by Dr. John Slough at the University of Washington. It is a very simple concept that promises stunning velocities anywhere from 400 to 900 km/second, the entire system being based on the Tesla double winding, single phase, capacitor, induction motor. The only difference between the above mentioned motor is that there isn't a rotor suspended in the middle of the windings, and the windings are larger in diameter (20 meters) and are shaped in loops (round), and offset 90° from one another...a polyphase loop antenna. 1000 watts is fed sequentially into the loops and creates a rotating electromagnetic field (RMF). The rate (speed) of rotation is "tuned" to be much faster than the ions of the solar wind can be caught in (per their weight), and just below the cyclotron resonant frequecy of the solar wind electrons. This results in the electrons being "captured" in the RMF which expands to radii orders of magnitude greater than the radius of the polyphase antenna. The diameter of the of the rotating electron populated field is determined (held in check) by the dynamic pressure of the solar wind. In this example the outside diameter = ~100 km. This "sail" is pushed by the heavy ions of the wind and depending on which value one uses between 1 and 6 nano pascals wind pressure, Newtons of force are produced. Eg. 2.5 nano pascals will create 19-20 Newtons of force.
As the sail moves away from the Sun it expands and thereby, ostensibly, continues to produce constant acceleration. Kevin
Attached are the papers

 

[steelpillow]

Fascinating stuff, thank you for posting it here. The basic physics and concept look sound, as they should with NASA supporting it. Any problems will most likely be practical engineering ones. Some which spring to the mind of a retired EM engineer:

Constantly accelerating ions one way round the ring and electrons the other is likely to create some imbalance, due to differing mass/charge ratios and mobilities. This will create a torque on the field generator, which must be engineered in.

Terrestrial high-power systems and rotating machines (as we call dynamos and electric motors) use three-phase generation, as it evens out the torque and avoids mechanical vibration at harmonics of the AC frequency. In this case I would guess that the relevant frequency is the rotational period of the plasma, though that will be different for electrons and ions, so ironing out those multiple harmonics might be a wise precaution. A practical field generator will likely want to move from the twin-pair coil arrangement to a three-phase triplet.

The unanticipated emission of electromagnetic energy is always a risk with any engineered EM system. The physics seldom respects the designer's thought processes and, like water in a leaky bucket, will find any weaknesses and exploit them blindly. Problems which this can bring include interference with other equipment nearby, susceptibility to interference from other EM power systems nearby (such as a rendezvous between two such craft), and radiation of sufficient wasted power that it reduces the overall propulsive efficiency. The field harmonics noted above offer a typical example. So the electromagnetic compatibility (EMC) control plan is likely to be a key focus in making this a practical proposition.

On a more speculative note, I wonder if it would prove possible to angle the craft so that it would, to at least some extent, sail across the solar wind like a nautical schooner? Tacking against the solar wind would appear impractical, unless some equivalent of a keel to resist sideways movement can be devised.

 

[publiusr]

Maybe time such an interaction to coincide with a planetary flyby, to use its field?

Even if it wasn’t done as a Voyager type boost. It could be the opposite…the craft might do a true epicycle—fall sunward a bit, then move back outward. No other craft could do that. Ion bus for back-up.

 

[publiusr]

A couple of news items concerning the advancement of solar sails:

"New technique could speed up the development of acoustic lenses, impact resistant films and other futuristic materials."

and--

"Researchers develop neutron-shielding film for radiation protection." ---both from phys.org

This MXene-Boron carbide composite is 1,000 times thinner than other shielding.

Now, if a spray of fissile material could be deposited on this--might we have a fission-fragment "rad-sail" that could also use photon pressure, starwisp type magnetics and a particle beam to spike the fissile coating?