Plasma Signatures of Small Orbital Debris

Using first-principles modeling, we investigate ion acoustic soliton generation by small charged debris in different plasma regimes relevant to laboratory and low-Earth orbit (LEO) plasma. In recent years, the number of orbital debris has skyrocketed to levels that threaten the present and future use of space. Among the various populations of orbital debris, the small, <10 cm debris are particularly problematic. With an average orbital speed of 10 km/s in LEO, they can create significant damage upon impact. New methods for detection, tracking and removal of this class of orbital debris are sorely needed. A new idea for indirect orbital debris detection via nonlinear plasma signatures has been recently proposed. The concept stems from the fact that the debris moves hypersonically in the ambient plasma and gets charged by collecting plasma particles and by electron emission processes. The interaction of charged debris with the ambient plasma can generates ion acoustic precursor solitons, which are non-linear waves where non-linear effects balance dispersion. Thus, a soliton can propagate unchanged in a homogeneous medium. Plasma signatures that can propagate way from the debris are particularly interesting as a potential indirect method of debris detection and tracking.