Epälineaariset plasma-aaltoilmiöt aurinkotuulen ja magneettikehän vuorovaikutuksessa
Year: 2025
Type: dissertation
Abstract: The Earth's magnetosphere is the magnetic domain surrounding the Earth which is shielded from the solar wind, a continuous supersonic plasma stream from the Sun. Plasma waves generated within and in the vicinity of the magnetosphere are an important mechanism for the solar wind driving of the magnetosphere. This thesis investigates two plasma wave phenomena integral to the solar wind-magnetosphere interaction, in which non-linear plasma wave evolution plays a role. To model these phenomena, hybrid-kinetic simulations are used, which capture the ion kinetic physics necessary for these phenomena to occur. The first topic of this thesis are foreshock transients, which form upstream of the Earth's magnetosphere due to non-linear interaction between foreshock plasma waves. This thesis models the transient development, presenting a report of the transients' formation rate, propagation and evolutionary characteristics. The findings provide a reference for in-situ spacecraft measurements, and reveal new details on the transient evolution. The second topic of this thesis are Kelvin-Helmholtz surface waves generated along the magnetopause, the boundary separating the magnetosphere from the solar wind. This thesis identifies observable signatures of Kelvin-Helmholtz wave-driven finite Larmor radius ion mixing, and subsequently presents in-situ evidence of such mixing, which indicates that it is a viable pathway for the solar wind plasma entry into the magnetosphere.
Source: Työväentutkimus Vuosikirja
Author: Tarvus, Vertti
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7199738334