A Plasma-Beam Shepherd: Neutralised Particle-Beam Momentum Transfer to a 170-Metre Asteroid

This paper computes a plasma-beam shepherd that directs 260,000 W of beam power at 48,000 m per second toward a 170 m asteroid of mass 6,173,857,883 kg. Beam momentum flux reduced by a coupling fraction of 0.66 gives an effective force of 3.58 N and an acceleration of 5.79e-10 m per second squared. Over 4 years the shepherd delivers 73.1 mm per second against a requirement of 23.9 mm per second for a 9,500 km displacement with nine years of warning, a margin ratio of 3.06 and a computed separation of 29,064 km. This is a computed study of a deflection system for planetary defence, with no targeting or weapon application. It is simulated, not measured.