Probing the Field Line Resonances in response to Foreshock Waves using 3-D Global Hybrid Simulations

Abstract:

Field line resonances (FLRs), also known as standing Alfven wave resonances, are one of the ubiquitously existing ultra-low frequency (ULF) wave modes in the magnetosphere. Recent observations and simulations have shown that the FLRs are driven by compressional foreshock disturbances. However, all those studies are performed under limited solar wind conditions, i.e., a more comprehensive study of how the solar wind conditions affects the FLRs in the magnetosphere is still missing. In order to address this issue, we employ a 3-D global hybrid model to investigate the azimuthal and north-south structure of the foreshock driven FLRs in the solar wind-magnetosphere coupled system. The self-generated compressional foreshock waves will first be identified in the foreshock region and traced into the magnetosphere. The standing shear Alfven waves and the FLR harmonics under radial and oblique IMF and various solar wind conditions in response to these foreshock waves will then be presented. Finally, we will report the global effects of FLRs in the magnetosphere between quasi-parallel and quasi-perpendicular shocks.