Mass Separaton by Oscillating Electromagnetic Fields

It is shown that if the phase difference between oscillating electric and magnetic field is judiciously chosen, particles are accelerated along a line that is perpendicular to those fields. Moreover, the direction of acceleration depends on the particle mass, so that species of (even small) mass difference, are accelerated in opposite directions. Two configurations are addressed. One configuration is of a linearly-polarized electric and magnetic fields. In a second configuration, a steady axial magnetic field is added to circularly-polarized oscillating fields. For an appropriate phase difference, charged particles, the cyclotron frequencies of which lie on the two opposite sides of the cyclotron resonance, are accelerated in opposite directions. Ion collisions with neutrals cause the ion acceleration to result in a drift velocity of the ions. Surprisingly, the collisions do not impede the mass separation. The direction of the drift also depends on mass. Mass separation, separation of particles of different mass, is a crucial process in a variety of societal applications [1]–[3]. This phase-induced mass-selective acceleration presented here can be the basis for a novel mass separation scheme.