In:
Frontiers in Astronomy and Space Sciences, Frontiers Media SA, Vol. 9 ( 2022-9-2)
Abstract:
Ultra-low frequency (ULF) waves are routinely observed in Earth’s dayside magnetosphere. Here we investigate the influence of externally-driven density variations in the near-Earth space in the ULF regime using global 2D simulations performed with the hybrid-Vlasov model Vlasiator. With the new time-varying boundary setup, we introduce a monochromatic Pc5 range periodic density variation in the solar wind. A breathing motion of the magnetopause and changes in the bow shock standoff position are caused by the density variation, the time lag between which is found to be consistent with propagation at fast magnetohydrodynamic speed. The oscillations also create large-scale stripes of variations in the magnetosheath and modulate the mirror and electromagnetic ion cyclotron modes. We characterize the spatial-temporal properties of ULF waves at different phases of the variation. Less prominent EMIC and mirror mode wave activities near the center of magnetosheath are observed with decreasing upstream Mach number. The EMIC wave occurrence is strongly related to pressure anisotropy and β ‖ , both vary as a function of the upstream conditions, whereas the mirror mode occurrence is highly influenced by fast waves generated from upstream density variations.
Type of Medium:
Online Resource
ISSN:
2296-987X
DOI:
10.3389/fspas.2022.984918
DOI:
10.3389/fspas.2022.984918.s001
DOI:
10.3389/fspas.2022.984918.s002
DOI:
10.3389/fspas.2022.984918.s003
DOI:
10.3389/fspas.2022.984918.s004
DOI:
10.3389/fspas.2022.984918.s005
DOI:
10.3389/fspas.2022.984918.s006
DOI:
10.3389/fspas.2022.984918.s007
DOI:
10.3389/fspas.2022.984918.s008
DOI:
10.3389/fspas.2022.984918.s009
DOI:
10.3389/fspas.2022.984918.s010
DOI:
10.3389/fspas.2022.984918.s011
DOI:
10.3389/fspas.2022.984918.s012
DOI:
10.3389/fspas.2022.984918.s013
Language:
Unknown
Publisher:
Frontiers Media SA
Publication Date:
2022
detail.hit.zdb_id:
2778829-5
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