Measuring the turbulent energy cascade rate with multiple spacecraft

Exploration of space plasmas is entering a new era of multi-satellite constellation measurements that will determine fundamental properties of turbulence, with unprecedented precision. Familiar but imprecise approximations must be abandoned and replaced with more advanced approaches. We present the novel multispacecraft technique LPDE (Lag-Polyhedra Derivative Ensemble) for evaluating third-order statistics, using simultaneous measurements at many points. The method differs from existing approaches in that (i) it is inherently three-dimensional; (ii) it provides a statistically significant number of estimates from a single data stream; and (iii) it allows for a direct visualization of energy flux in turbulent plasma. Implications for HelioSwarm and Plasma Observatory and comparison with single-spacecraft approaches are discussed.