Magnetic sail significant in the long term. In typical magnetic sail designs, the magnetic field is generated by a loop of superconducting wire. Because loops of current-carrying conductors tend to be forced outwards towards a circular shape by their own magnetic field, the sail could be deployed simply by unspooling the conductor and applying a current through it. The solar wind is a continuous stream of plasma that flows outwards from the Sun: near the Earth's orbit, it contains several million protons and electrons per cubic meter and flows at . The magnetic sail introduces a magnetic field into this plasma flow
Two-stream instability in various limiting cases as beam-plasma instability, beam instability, or bump-on-tail instability. Consider a cold, uniform, and unmagnetized plasma, where ions are stationary and the electrons have velocity formula_1, that is, the reference frame is moving with the ion stream. Let the electrostatic waves be of the form: formula_2 Applying linearization techniques to the equation of motions for both species, to the equation of continuity, and Poisson's equation, and introducing the spatial and temporal harmonic operators formula_3, formula_4 we can get the following expression: formula_5 which represents the dispersion relation for longitudinal waves, and represents a quartic equation in formula_6.