Probing the System at 800 km/s

Finnish scientists have invented an electric solar sail that could carry a space probe out of the solar system in 15 years.

The solar wind is a very tenuous but high speed (300-800 km/s) plasma stream blowing radially outward from the Sun. The solar wind powers the aurora and governs space weather. The average dynamic pressure (force per unit area) of the solar wind is 2 nanopascal, corresponding to 0.2 grams weight per square kilometre.

Using such a weak dynamic pressure for pushing a spacecraft requires a very large area sail, much larger than what can be provided by a solid surface. In the electric sail, the sail is formed by an electric field existing around a thin, charged tether whose voltage is maintained by an onboard solar-powered electron gun. A 20-km long tether made of wire which is thinner than human hair fits in a small reel, but gives a square kilometre effective area when stretched out in space and charged. In the paper published today in Annales Geophysicae , two-dimensional first-principles plasma simulations run on a supercomputer were used to compute the thrust per unit tether length in different solar wind conditions and tether voltages to check the feasibility of the method. Theoretical analysis and one-dimensional simulations were used to validate the results.

The results indicate that ~50 nN/m force per unit length of the tether can be achieved in average solar wind, which could enable final speeds in the range 50-100 km/s (10-20 AU/year) for a lightweight spacecraft. At such high speed one could reach e.g. Pluto in less than four years and fly out of the heliosphere into interstellar space in less than 15 years.

Source

The concept of the electric sail is similar to the magnetic sail, or the mini-magnetospheric plasma sail. The trick is to devise a large electromagnetic sail that would interact with the solar wind without being destroyed by it.

Understand, this is strictly a one-way ride to the outer system and beyond. Of course if you can find reaction mass or rocket fuel out there, you may be able to devise a method of return. Buena suerte!