Field electron emission from gold dust grains

There is a number of areas in space where hot electrons represent a substantial constituent of the plasma environment, In such a case, any immersed dust grain could reach a very high negative surface potential. This potential is then limited by the field electron emission. In present contribution, we continue our previous investigation using 3D-electrodynamic quadrupole for dust grain trapping. We are able to charge a single trapped grain up to several hundreds of volts of negative surface potential using an electron gun. This potential is sufficient for observations of the field emission from micron size grains. Because there is lack of data on field electron emission from dielectric materials, we use gold spheres. Observed work function was in accordance with tabulated value. Nevertheless, the coarseness of the grains surfaces should be taken into account.