Foreshock cavitons for different interplanetary magnetic field geometries: Simulations and observations

• DOI: 10.1029/2010ja016413
• Publication Date: 2011-09-06T20:00:47Z
• Authors: X. Blanco-Cano; P. Kajdič; N. Omidi; C. T. Russell
• Keywords: 0103 physical sciences; 01 natural sciences; 0105 earth and related environmental sciences

[1] Global hybrid (kinetic ions, fluid electrons) simulations have shown the existence of foreshock cavitons characterized by large depressions in plasma density and magnetic field magnitude, bounded enhancements these two parameters. Foreshock share some characteristics with reported cavities, but contrast to cavities that often appear as isolated structures, are always found surrounded a sea ultra low frequency (ULF) waves. They occur regions deep foreshock, downstream from ion ULF wave boundaries. We perform global show can form for variety interplanetary (IMF) geometries different solar wind Mach numbers. use Cluster data common feature, they IMF orientations, consistent our simulation results. find decrements 60% ambient values. immersed where waves transverse compressive components presence diffuse distributions. linear kinetic theory estimate growth types responsible caviton formation, i.e., weakly oblique propagating linearly polarized Some observed trains high-frequency inside them this is predictions local higher-resolution simulations.