Magnetic Sails
Another energy source that emanates from the sun is solar wind. This wind is plasma, protons and electrons, which flow constantly in all direction and at the speed of about 500 km/s. We never encounter such a force on earth due to our protective magnetosphere. If the magnetosphere blocks out this force, then it much feel some form of drag. It would be plausible to create an artificial magnetosphere on a spacecraft and use that drag/ force to propel the ship. The amount of plasma per square kilometer is far less than that of sunlight. However, through the use of high temperature super conductors, a field could be created which would be much larger than any solar sail that could be manufactured. If practical, high temperature superconducting cable can be made to the grade which low temperature superconducting cable is made today, then the thrust – to – weight ratios of such a ship would be hundreds of times better than a ship with a 10 micron thick solar sail. The Magsail would also be very easy to deploy. Unlike a solar sail, the Magsail would be made of rugged cable and not a thin plastic film. Also, due to magnetic forces, this cable’s insulation would automatically inflate itself into a stiff hoop when electrical current was sent through the cable. It would take some energy to get the current flowing but none would need to be added because superconducting wire has no electrical resistance. Once the current was put into the cable, no further power would be needed to keep the current going.
The advantages of such a propulsion system is no needed propellant and the fact that a ship co – orbiting the sun and earth could go to any planet in the universe by just turning the power on the Magsail up or down. However, Magsails are not practical now because the cable that is needed by the system does not exist. But, advances in this field are being made quite rapidly and are making the practicality of such propulsion greater by the day.