The Perturbation of Interplanetary Dust Grains by the Solar Wind.

It is expected that photoelectric emission from the interplanetary dust grains leads to a positive charge the order of 10 volts on each grain. The Lorentz forces exerted on this charge by the magnetic fields . ied in the solar wind produce large perturbations in the Kepler orbits of the grains. On the assumpn that the sign of the interplanetary magnetic field reverses every few days, it is shown that the orbital lination of particles with radii equal to or smaller than about 1 X 10- cm at the orbit of Earth is atly increased by the Lorentz forces The importance of the Lorentz perturbation increases with the tance from the Sun.