Appendix to “Coulomb interactions in Ga LMIS” by Radlička and Lencová

This appendix comments on the input data and simulation results of Radlička and Lencová (RL), reported in the preceding paper. These simulations relate to the effects of space-charge on the full-width at half-maximum (FWHM) of the ion energy distribution from a gallium liquid metal ion source (LMIS), and on its virtual source size. Corrections are necessary to the input data, relating to LMIS shape, that were supplied by the present author. It is clear from RLʹs work that their simulations, when applied to the corrected shape data, would generate very good agreement between experimental results and numerical simulations concerning the FWHM. This work confirms that an inappropriate hydrodynamic condition has been used in past modelling programmes for LMIS shapes and current/voltage characteristics; consequently, some quantitative results from these old programmes must be considered unreliable in detail, especially at low emission currents, although qualitative trends have been correctly exhibited.