Electrostatic lofting conditions of single dust particles on a solid surface

We present experimental results on the initial lofting conditions of single dust particles resting on a solid surface when exposed to a 120 eV electron beam. Lofting is characterized as a function of particle size (10–70 μm in radii) and shape (jagged vs spherical). Similar to previous measurements of particles lofted from a dust pile, vertical launch velocities show an inverse relationship with the particle size and broad distributions for same-sized particles. Different from piled dust, the lofting velocities of single particles depend only weakly on the shape of the particles as also found in modeling. It is shown that jagged single particles have lower lofting velocities than jagged piled particles, while spherical single particles are lofted at higher velocities, compared to spherical piled particles. Based on the patched charge model (PCM) for piled particles and PCM for single particles (PCM-SP) on a solid surface, these results indicate that differences in the formation of microcavities for different scenarios play a role in determining the charging and lofting of dust particles.