1,3,- 1State Key Laboratory for Turbulence and Complex Systems, Peking University, Beijing 100871, China and School of Mechanics and Engineering Science, Peking University, Beijing 100871, China
- 2Department of Physics and Astronomy, University of Delaware, DE 19716, USA
- 3Institute of Space Physics and Applied Technology, Peking University, Beijing 100871, China and State Key Laboratory of Solar Activity and Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China
- 4School of Chemical and Physical Sciences, Victoria University of Wellington, Kelburn, Wellington 6012, New Zealand
- 5Department of Physics, University of Maryland, College Park, MD 20742, USA
- 6Guangdong-Hong Kong-Macao Joint Laboratory for Data-Driven Fluid Mechanics and Engineering Applications, Southern University of Science and Technology, Shenzhen 518055, PR China and Guangdong Provincial Key Laboratory of Turbulence Research and Applicatio
The Pressure--Strain interaction, - (Pα • ∇ )•uα , is a fundamental diagnostic for energy conversion in collisionless space plasmas, facilitating the exchange between bulk kinetic and internal energy for both electrons (α=e) and ions (α=i) without collisional dissipation. This interaction is traditionally decomposed into two distinct physical processes: the isotropic component pθ, associated with dilatation, and the anisotropic component Pi-D, related to deviatoric deformation.
In this study, we perform a synchronized statistical analysis of these components by integrating Particle-In-Cell (PIC) simulations with in-situ observations from the Magnetospheric Multiscale (MMS) mission. By examining probability distribution functions (PDFs) and employing coarse-graining techniques, we identify contrasting statistical signatures for pθ and Pi-D. Our results indicate that pθ exhibits nearly Gaussian PDFs with kurtosis values close to a normal distribution, suggesting relatively homogeneous fluctuations across the plasma. In contrast, Pi-D displays sharply peaked, heavy-tailed PDFs, with these tails persisting even at large scales. Notably, the extreme events within the Pi-D tails are spatially correlated with coherent structures, such as current sheets and vortices.
Furthermore, scale-dependent filtering reveals that both pθ and Pi-D are highly sensitive to the analysis scale. However, a significant divergence is observed between PIC simulations and MMS data regarding their scale-dependent behaviors, highlighting potential differences between numerical modeling and high-resolution observations. We conclude that pθ serves as a distributed background channel for energy exchange, while Pi-D acts as a localized, intermittent channel. These findings clarify the statistical nature of the Pressure--Strain interaction and offer critical insights into the dissipation pathways and heating mechanisms within turbulent space environments.
How to cite: Ye, Y., Yang, Y., Wang, S., Parashar, T., Wang, Y., Wan, M., and Shi, Y.: Pressure–Strain Interaction in Collisionless Plasma Turbulence: Statistics and Scale Dependence, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7850, https://doi.org/10.5194/egusphere-egu26-7850, 2026.
