Dissertation Defense: "Transport of magnetic fields and cosmic rays in the turbulent interstellar médium"

Turbulence, magnetic fields, and cosmic rays are components of the interstellar medium of our galaxy and are strongly coupled through complex plasma processes. The magnetic flux transport in molecular clouds is essential in understanding different processes involved in stellar formation. The cosmic ray transport in the vicinities of supernova shocks is necessary to understand how the acceleration process of the galactic cosmic rays occurs. Both transports are controlled in an efficient form by turbulence. In this project, we studied the basic mechanisms of the magnetic flux transport in the presence of magneto-hydrodynamic (MHD) turbulence, and we also investigated how the cosmic rays that diffuse in a shock front can amplify the magnetic fields and affect the efficiency of the confinement and acceleration of these particles in that region. For that, we developed numerical experiments by 3D MHD simulations and Particle- in-Cell-MHD 2D to characterize, quantitatively, the turbulence effect in the transport of magnetic fields and cosmic rays.to the cluster and stars not belonging to the main sequence nor members of the cluster, such as foreground objects and/or evolved stars. The obtained result consisted of 44 and 47 stars classified as CBes in the S-PLUS magnitudes set, and a total of 206 and 289 objects classified as CBes in the SOAR set, for k-NN and DT predictions, respectively. In the SOAR ensemble, the DT model estimated a minimum CBe/(B + CBe) fraction of 26%. For both estimators, almost every CBe with Hα emission was classified as a candidate. One of the remarkable results also lies on the prediction of CBe candidates in the "redde" side of the MS, location of inactive CBes or systems with less dense disks (e.g., the beginning of building-up or end of dissipation phases). As the first work to consider every known properties of CBe disks in the formulation of the synthetic cluster, it can be stated that our developed methodology is promising as a preliminary analysis resulted in a higher CBe content than previous estimates, including high resolution spectroscopic surveys, when taking into account the same magnitude depth.

Keywords: magnetic fields, cosmic rays, interstellar medium, turbulence, magnetohydrodynamics, magnetic reconnection