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Hybrid Vigour
Q: Can we combine a sunlight sail having high light pressure, with a robust plasma sail (M2P2) having easy deployment?
A: Yes, by suspending opaque material in M2P2.
- For each 1% change in albedo, we increase the thrust by 50X compared to solar wind alone (at Earth orbit).
- Optically thick plasma < 1% opacity
- Narrow absorption lines = little opacity at the estimated densities (<1012/cc)
- Rare-Earth oxides (many atomic lines)
- Polycyclic Aromatic Hydrocarbons
- Diffuse Interstellar Bands (broad absorption lines)
Notes:
The question is whether we can combine a solar photon sail, that uses the high light pressure from the Sun, with a robust magnetic plasma sail, that has easy deployment and indestructible sails. The answer is yes, provided we can find an opaque material to make the magnetic plasma sail reflect or absorb sunlight. Absorbing sunlight is only half as efficient as reflecting, but it doesnt really matter because even 1% opacity will provide fifty times the thrust of the solar wind alone. Now there are many plasmas that have a color to them, which means they absorb light from the sun, the bright red color of neon plasma is a well known feature of neon signs. But all such atomic and molecular absorptions are only a narrow portion of the solar spectrum, and though we havent conducted a comprehensive search, we dont expect to find any plasma approaching 1% opacity. On the other hand, unlike the narrow colors absorbed by molecules, dust absorbs everything and is just plain black. The opacity then depends only on the quantity of dust suspended in the plasma.
How do we suspend dust in a plasma sail? Several experiments (coming from the hot new field of dusty plasmas) show the way.