Parametric Study of the Performance of an Electrostatic Analyzer With an Hemispheric Field-of-View Based on the Donut Topology

We carried out a parametric study of the optical performance of an electrostatic analyzer based on the donut topology. The instantaneous hemispheric field-of-view of the optics eliminates the need of electrostatic deflectors, which are usually added to the energy analyzer in other designs to cover such a wide field-of-view. Parametrization of the donut topology and the use of parallel computing have enabled a wide parametric study of the instrument's performance as a function of the angle resolution of the instrument. We have identified a limited number of geometric parameters, including the outer radius of the detection system, which determine the geometric factor and energy resolution of the instrument for a given angular resolution. The average geometric factor per pixel of this 3D plasma camera varies in the range (Formula presented.) with an energy resolution between 9% and 14% for an energy limit of 20 keV. Our results suggest that a wide range of space missions could benefit from this new instrument concept. A low-angular-resolution version of the instrument could be installed on a nano-satellite platform, for example, for space weather monitoring on low-Earth orbit. For space missions requiring high-angular-resolution measurements, a high-temporal-resolution plasma camera would be able to provide the detailed distribution function of charged particles on larger platforms.