I need to find the correct voltage to apply to a wire grid in order to repel a plasma of which I know the density (free electrons per volume) and the particle energy in eV. I see a Debye sheath as being analogous to what I will create with such a charge. The way I see it is that I will have two wire layers at opposite potentials, creating a capacitance in between them, and this will create an outside charge. This charge will repel the plasma on the outside so that it does not enter the system. Would someone tell me what I need to consider in order to solve this problem? I understand that different voltages would achieve a larger or smaller distance between the outside wire grid and the plasma, more or less debye lengths, but is there a saturation point, a voltage beyond which the distance would not be noticeably increased? How do I go about calculating this voltage? Thank you!