Beyond Boltzmann: Modelling Non-Equilibrium Space Plasmas Through Kappa Distributions

• Grant number: 24/14163-3
• Support Opportunities: Scholarships in Brazil - Support Program for Fixating Young Doctors
• Start date: September 01, 2024
• End date: August 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Agreement: CNPq
• Principal Investigator: Jose Ademir Sales de Lima
• Grantee: Monã Hegel Benetti
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 24/02295-2 - Beyond Boltzmann: Modelling Non-Equilibrium Space Plasmas Through Kappa Distributions, AP.R

Abstract

In this project we investigate space plasmas out of thermodynamic equilibrium based on kappa (non-Gaussian) distributions. The standard kappa distribution has been the most explored statistical tool to study the suprathermal component of space plasmas in solar winds and planetary magnetospheres. The basic reason is its agreement with measurements from missions like Voyager, HELIOS, WIND, Cluster spacecraft and the Parker Solar Probe. However, as an empirical distribution, it has only a finite number of non-divergent velocity moments. Such a problem was solved by the regularized kappa distribution, proposed for suppressing the singularities plaguing the standard kappa distribution. In this context, we will derive the suprathermal equation of state based on the improved kappa distribution. This result leads naturally to the equation describing the spatial and temporal evolution of the electron distribution in the heliosphere thereby allowing us to study the instability and electromagnetic wave emissions (bursts) occurring in the interaction of solar winds with the interplanetary plasma. Such results will be confronted with the observational data released by the space plasma probes. As an extra bonus, all the kappa predictions will be compared with the ones derived from the non-Gaussian Tsallis statistics. (AU)