FR1.2: Non-equilibrium electron kinetics
Goal: To develop a kinetic description of electron transport processes in collisionless and collisional
plasma
Challenges: A kinetic description of transport processes is a critical but largely unsolved problem in collisionless and collisional plasma.
Background: Electron kinetics determines ionization processes and chemical reactions in gas discharge plasmas.
Collisionless magnetized plasma exhibits “collisionality” due to instabilities/turbulence and wave-particle interactions, resulting in electron and ion acceleration, dissipative heating, and non-classical heat transport. Many phenomena in gas discharges share common ground with space plasmas.
Proposed Research: We develop the theory and computational tools to describe power coupling to electrons in weakly-collisional plasmas and analyze collisionless heating, anomalous skin effect, and magnetic pumping caused by non-local kinetics and electrodynamics. We also develop kinetic models for the solar wind that describe coronal heating, solar wind acceleration, and the evolution of the solar wind from the corona to the heliospheric termination shock.
Impacts: Incorporating kinetic electron physics including the heat flux remains an outstanding problem in heliospheric physics. The proposed work will advance the state-of-the-art by providing a novel kinetic treatment of electrons within the framework of a gyrotropic description of protons that incorporates cutting-edge MHD turbulence transport models.
FR1.2a: Electron kinetics in gas discharges
Weakly-ionized low-temperature plasmas are prone to instabilities and self-organization. Striations have been observed long before Langmuir introduced the term plasma. Although their origin as ionization waves became clear by the end of the 70 th , the interplay between the nonlinear and kinetic effects responsible for plasma stratification remains unclear. Using a self-consistent hybrid model of collisional plasma, we have obtained moving striations in DC discharges of noble gases. Further model development will allow study transitions between different wave types observed in experiments and
selecting appropriate discharge conditions for specific applications.
Image 1 shows the calculated contours of Electron Energy Probability Function and the electric field profile for ionization waves in Neon. The solid white line shows the electric potential. The dashed lines show the excitation and ionization thresholds. [From Kolobov and Arslanbekov, Ionization waves in low-current DC discharges in noble gases obtained with a hybrid kinetic-fluid model, arXiv:2208.14321 physics.plasm-ph, submitted for publication in Physical Review
E].
