Head: Andrey Divin
Number: RNF 23-22-00386
Description:
Fast collimated plasma clumps, known as jets, are observed in a wide variety of plasma media and exist over a wide range of parameters. Events of this kind are especially characteristic of astrophysical and heliospheric plasmas. In this case, the energetic plasma displaces the background medium and the magnetic field, generating perturbations at distances much larger than the size of the source.
A number of fundamental problems that are being solved in this project require both new experimental data and adequate numerical calculations. The main component of the project will be 3D modeling with a kinetic code, which will allow combining microscopic and macroscopic interaction dynamics. The computational code makes it possible to track the trajectories of particles of various types and to quantify the role of various processes. The following fundamental questions will be considered in the project: 1) what processes determine the rate of cavity collapse; 2) how does the magnetic field penetrate into the cavity center at the stage when the cloud is still expanding; 3) what is the role of kinetic microinstabilities and the Hall effect. With the help of kinetic modeling, the energy balance and transformation of the initial energy of the expanding cloud will be studied, and the influence of the chemical composition of the initial cloud will be studied.
Work in 2023-2024 is being carried out jointly with the Institute of Laser Physics of the Siberian Branch of the Russian Academy of Sciences, which has a stand KI-1 ("Space Research - 1"). The facility is intended for laboratory research of active phenomena in space plasma. The experiment provides extensive diagnostic possibilities for measuring plasma parameters with probes and optical means. Within the framework of this project, a series of experiments is being carried out at the KI-1 stand, in which either a spherical cloud of laser plasma or directed flows expanding into the background medium will be formed using laser radiation.
Based on the results of three-dimensional numerical simulation, a model will be created for the expansion of an energetic plasma cloud with parameters characteristic of a number of active experiments in the Earth's magnetosphere, as well as laboratory experiments at the KI-1 facility. Variants with background plasma (super-Alfven expansion), as well as an expansion into vacuum with a magnetic field (sub-Alfven expansion) are considered. Based on the results of studying the dynamics of cloud deceleration, a conclusion will be made about the role of anomalous diffusion when a magnetic field is introduced into the forming caverns at a late stage, and a qualitative and quantitative comparison will be made with a laboratory experiment.