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 m 11.8 m 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.

The kinetic effects on the dust particles are studied experimentally in a plasma crystal locally irradiated by a narrow pulsed electron beam with an energy of 13 keV and a peak current of 4 mA. We observe in the top layer of the plasma crystal the formation of a stable dust flow along the irradiation direction in the first ≈200 ms of the interaction. The dust flow eventually becomes perturbed later in time, with the dust particles having chaotic trajectories as they are still drifting in the beam direction. The speed of the dust flow is mapped in a horizontal plane using the particle image velocimetry technique (PIV). The kinetic energy of the flow and its vorticity are deduced based on the speed vectors provided by PIV. A maximum energy transfer factor ≈0.048 from the electron beam is inferred considering the peak kinetic energy (≈625 eV) of the dust flow. Vortices and tripolar vortices are observed when the dust flow becomes perturbed.

Dust is a challenge for the design and operation of equipment on the Martian surface, particularly for solar cells. An efficient and robust technique for removing dust and sand from surfaces immersed in CO 2 at low pressure is presented. The working principle is based on a pulsed plasma jet produced between two coaxial electrodes biased at voltages between 1 and 2 kV. A demonstration is presented using dust particles whose chemical composition mimic the Mars soil. An array of connected photovoltaic cells fully covered with dust and sand is exposed to the plasma jet. The cells open circuit voltage is monitored in real-time thus providing the means to measure the dust removal efficiency. A good cleaning efficiency is attained after a few shots in a geometry where the plasma jet is directed perpendicularly to the dusty surface. The main advantage of this approach lies in the opportunity to apply it directly at about 5 Torr, the pressure of the Martian environment. A numerical evaluation shows that the plasma drag force on a dust particle is orders of magnitude higher than its weight depending on plasma density and flow speed, hence validating the principles of this cleaning technique.

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