Pc5 Wave Activity from 2D Hybrid-Vlasov Simulations

Kuvaus

Ultra-low frequency (ULF) waves in the Pc5 range, with periods between 150
– 600 s, play a key role in the dynamics of Earth’s magnetosphere, in
particular through their interaction with radiation belt electrons. One
important source of magnetospheric Pc5 waves are fluctuations of the
upstream solar wind parameters in the same frequency range. Pressure
variations in the solar wind are thought to result in a forced breathing
of the magnetosphere, as the magnetosphere would expand and compress in
response to the changing upstream conditions, which drives ULF waves
inside the magnetosphere. The details of the interaction of these solar
wind variations with the Earth’s bow shock and magnetosheath, their impact
on the magnetosheath plasma properties and how the fluctuations would
change before reaching the magnetopause, remain however unclear. In this
study, we investigate the influence of externally-driven density
variations in the near-Earth space using global 2D simulations performed
with the hybrid-Vlasov model Vlasiator. The new time-varying boundary
setup in Vlasiator allows us to set Pc5 periodic density pulses coming
from the upstream. The density pulses cause the breathing motion of the
bow shock, create clear stripes of variations inside the magnetosheath,
and modulate the electromagnetic ion cyclotron (EMIC) and mirror modes. We
characterize the spatial-temporal variations of waves on the simulation
plane within the magnetosheath and discuss the potential impact on the
near-Earth environment.

Aikajakso	29 maalisk. 2023 → 31 maalisk. 2023
Tapahtuman otsikko	Physics Days 2023
Tapahtuman tyyppi	Konferenssi
Sijainti	Tampere, SuomiNäytä kartalla
Tunnustuksen arvo	Kansallinen