Abstract Identifying the primary physical mechanisms and associated secondary processes (e.g., different plasma wave modes, instabilities and magnetic reconnection), that are responsible for plasma heating at the planetary magnetospheres and astrophysical plasmas is often difficult with a single spacecraft or even with a constellation of spacecraft within a single‐plasma scale. Here, we present a statistical study using data from four Magnetospheric Multiscale (MMS) satellites to characterize the cross‐scale plasma‐heating distributions associated with Kelvin‐Helmholtz instability (KHI) and drift mirror instability (DMI). We find that characteristic heating frequency (CHF) distributions follow distinct tail‐scaling regimes: KHI events exhibit low‐ power‐law‐like tails, whereas DMI events occupy larger‐ regimes closer to quasi‐Gaussian behavior. Comparison of a KHI event with Particle‐in‐Cell (PIC) simulations yields consistent tail‐scaling, supporting the physical interpretation. We also analyze an event with periodic encounters of diamagnetic cavities (DMCs) at the Earth's dayside magnetopause, and find that the CHF scaling together with KH growth‐rate analysis is consistent with KHI modulation of reconnection. These results establish statistical discrimination between KHI‐ and DMI‐associated heating, and can be used in future works to establish an automated identification of primary mesoscale processes driving cross‐scale non‐adiabatic heating in collisionless plasmas.
Nykyri et al. (Fri,) studied this question.