# Are there enough charged particles in space to power an ion drive without carrying your own particles?

It feels like a sci fi question but is more related to real science in present times so cannot be posted on scifi SE.

assume an engine made of a hollow solenoid with valves inside its hollow pipe part

now if we assume there are enough free moving charged particles in space we'll close the valve and collect the particles. After a certain amount of them have been accumulated open the valve and generate a momentary but extremely intense magnetic field using the solenoid which would propel the charged particles back and the engine forward.

It's very similar in principle to a rail gun. But the question is are there enough free moving charged particles of desirable polarity that can be used to drive a ion drive without having to carry it's own ion source?

• What part of space, the van Allen belts for example? The outer belt consists mainly of high energy (0.1–10 MeV) electrons trapped by the Earth's magnetosphere. You will need some way of removing excess charge from the craft, AFAIK. – user108787 Oct 3 '16 at 17:11
• Search term: Bussard ramjet.. The original assume you'll fuse the scooped material for power as well, but the notion is out there. It is, however, completely hypothetical. – dmckee Oct 3 '16 at 17:22

http://hypertextbook.com/facts/2000/DaWeiCai.shtml Acording to this, the is like 1 $atom/cm^3$ so I don't think this device can work only with the particles free in space. But I know that Nasa is working on a space engine called "Plasma propulsion engine", that accelerates the ions from the fuel futher using electromagnetic fields, to increase the efficiency of the engine getting more acceleration from the same amount of fuel.