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Title: Foreshock wave interaction with the magnetopause: Signatures of mode conversion

Our previous hybrid simulation under a radial interplanetary magnetic field (IMF) and a supercritical solar wind Mach number has shown that foreshock compressional waves originated from the quasi–parallel (Q–∥) shock are mode converted to kinetic Alfvén waves (KAWs) at the Alfvén resonance surface of the subsolar magnetopause. In this paper, three–dimensional global dayside mode conversion is investigated for cases under various solar wind conditions using the global hybrid model. The global patterns and propagations of KAWs are distinguished and presented. Under a near–critical Mach number ( MA=3), KAW structures due to mode conversion exhibit a feature of broader excitation regions in the magnetopause boundary layer (MPBL) compared to supercritical Mach number ( MA=5) shocks. For cases with an oblique IMF with supercritical Mach numbers ( MA=5), the amplitude of magnetosheath compressional waves is larger at the quasi–parallel shock (Q–∥) than at the quasi–perpendicular (Q–⊥) shock. Downstream of the Q–∥ shock, there is a general trend that the perturbations of density ( N) and magnetic field ( B) change from predominantly in–phase in the magnetosheath to antiphase near the MPBL. While downstream of the Q–⊥ shock, an antiphase relation between N and B is dominant throughout the magnetosheath and magnetopause exceptmore » near the shock transition. The compressional drivers are found to reach an extended region of the magnetopause due to the combined effects of wave propagation in the plasma frame and flow convection, leading to a broad region of mode conversion at the magnetopause. Subsequently, the resulting KAWs can be carried to the regions downstream of the Q–⊥ shock owing to the flow convection at the magnetopause. Furthermore the KAWs propagate poleward along the geomagnetic field lines and meanwhile are carried tailward by the ambient flows, and they are more intense in the downstream of Q–∥ shocks than downstream of Q–⊥ shocks.« less
Authors:
ORCiD logo [1] ;  [2] ; ORCiD logo [2] ; ORCiD logo [2]
  1. Univ. of New Hampshire, Durham, NH (United States)
  2. Auburn Univ., Auburn, AL (United States)
Publication Date:
Grant/Contract Number:
SC0010486
Type:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Space Physics
Additional Journal Information:
Journal Volume: 122; Journal Issue: 7; Journal ID: ISSN 2169-9380
Publisher:
American Geophysical Union
Research Org:
Auburn Univ., AL (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; mode conversion; hybrid simulation; MPBL; KAWs
OSTI Identifier:
1474281
Alternate Identifier(s):
OSTI ID: 1374903

Shi, Feng, Cheng, Lei, Lin, Yu, and Wang, Xueyi. Foreshock wave interaction with the magnetopause: Signatures of mode conversion. United States: N. p., Web. doi:10.1002/2016JA023114.
Shi, Feng, Cheng, Lei, Lin, Yu, & Wang, Xueyi. Foreshock wave interaction with the magnetopause: Signatures of mode conversion. United States. doi:10.1002/2016JA023114.
Shi, Feng, Cheng, Lei, Lin, Yu, and Wang, Xueyi. 2017. "Foreshock wave interaction with the magnetopause: Signatures of mode conversion". United States. doi:10.1002/2016JA023114. https://www.osti.gov/servlets/purl/1474281.
@article{osti_1474281,
title = {Foreshock wave interaction with the magnetopause: Signatures of mode conversion},
author = {Shi, Feng and Cheng, Lei and Lin, Yu and Wang, Xueyi},
abstractNote = {Our previous hybrid simulation under a radial interplanetary magnetic field (IMF) and a supercritical solar wind Mach number has shown that foreshock compressional waves originated from the quasi–parallel (Q–∥) shock are mode converted to kinetic Alfvén waves (KAWs) at the Alfvén resonance surface of the subsolar magnetopause. In this paper, three–dimensional global dayside mode conversion is investigated for cases under various solar wind conditions using the global hybrid model. The global patterns and propagations of KAWs are distinguished and presented. Under a near–critical Mach number (MA=3), KAW structures due to mode conversion exhibit a feature of broader excitation regions in the magnetopause boundary layer (MPBL) compared to supercritical Mach number (MA=5) shocks. For cases with an oblique IMF with supercritical Mach numbers (MA=5), the amplitude of magnetosheath compressional waves is larger at the quasi–parallel shock (Q–∥) than at the quasi–perpendicular (Q–⊥) shock. Downstream of the Q–∥ shock, there is a general trend that the perturbations of density (N) and magnetic field (B) change from predominantly in–phase in the magnetosheath to antiphase near the MPBL. While downstream of the Q–⊥ shock, an antiphase relation between N and B is dominant throughout the magnetosheath and magnetopause except near the shock transition. The compressional drivers are found to reach an extended region of the magnetopause due to the combined effects of wave propagation in the plasma frame and flow convection, leading to a broad region of mode conversion at the magnetopause. Subsequently, the resulting KAWs can be carried to the regions downstream of the Q–⊥ shock owing to the flow convection at the magnetopause. Furthermore the KAWs propagate poleward along the geomagnetic field lines and meanwhile are carried tailward by the ambient flows, and they are more intense in the downstream of Q–∥ shocks than downstream of Q–⊥ shocks.},
doi = {10.1002/2016JA023114},
journal = {Journal of Geophysical Research. Space Physics},
number = 7,
volume = 122,
place = {United States},
year = {2017},
month = {6}
}