Pushing microscopic matter in plasma with an electron beam

Manipulation of microscopic structures is routinely carried out by exploiting the light pressure of a focused laser beam. Here we use a pulsed electron beam (EB) with energy 10–14 keV and peak current 4 mA instead of a photon flux and demonstrate transport of microscopic matter over a few centimeters. Hundreds of electrically charged microspheres in diameter immersed in a radio-frequency plasma are driven into a flow with a speed of a few mm s−1 when irradiated by the EB. It is shown that the force associated with the electron momentum transfer is consistent with the observed acceleration of the microparticles (MPs) in gas at low pressure. Numerical estimates show that the electron drag force does not depend on the MP charge. The interaction of the EB is described in terms of the electron penetration depth, deposited energy and heating of the MPs, as well as the effect of the beam on the discharge. This proof of principles study has implications in dusty plasmas and beyond, in instances when MPs interact with sufficiently intense electron fluxes, and shows the potential to use an EB as a tool for displacing MPs.