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The GUMICS-4 global MHD magnetosphere-ionosphere coupling simulation
Janhunen, P.; Laitinen, T.; Facskó, G. +4 more
GUMICS-4 is a global magnetosphere-ionosphere coupling simulation based on global MHD magnetosphere and an electrostatic ionosphere. Here we review the development history, design and technical features of GUMICS-4 as well as a number of its postprocessing tools. We also compare GUMICS-4 predictions with observations for magnetopause distance, int…
On the origin of high-energy particles in the cusp diamagnetic cavity
Kronberg, E.; Daly, P.; Adamson, E. +2 more
We have analyzed Cluster magnetic field and plasma data during a high-altitude cusp crossing in 2003. The Cluster separation was ∼5000km and provided unique measurements of high energy particle properties both inside the DiaMagnetic Cavity (DMC) and surrounding magnetosheath. Most of the high energy electrons and protons had pitch angles of ∼90° i…
The role of electrons during chorus intensification: Energy source and energy loss
Zong, Q. -G.; Cao, J. B.; Huang, S. Y. +4 more
The role of electrons during the shock-induced chorus intensification observed by THEMIS D on 19 November 2007 is investigated in detail. First, the electrons are accelerated through the local betatron acceleration and radial diffusion, which are primarily in the perpendicular direction and result in the positive anisotropy (T⊥>T
Underestimates of magnetic flux in coupled MHD model solar wind solutions
Riley, Pete; Stevens, Michael L.; Linker, Jon A. +1 more
When validated with spacecraft observations, one enduring characteristic of global MHD solar wind models is the tendency to underestimate the interplanetary magnetic flux. This study quantifies the “missing flux” problem for models used in the coordinated Center for Integrated Space Weather Modeling study of corotating interaction regions, and ide…
Flux transfer events: Motion and signatures
Omidi, N.; Sibeck, D. G.
We present results from a 2.5 dimensional hybrid code simulation for the evolution of flux transfer events (FTEs) during intervals of due southward interplanetary magnetic field (IMF) orientation. The structures invariably form between pairs of reconnection lines, often remaining nearly stationary on the subsolar magnetopause before their motion b…
Simultaneous observations of the exterior cusp region
Chen, J.; Fritz, T. A.; Walsh, B. M.
A case study is presented analyzing the properties and spatial extent of the exterior cusp region. The dynamic nature of the exterior cusp makes the large scale properties difficult to measure using a single spacecraft. We use simultaneous cusp observations of the four Cluster spacecraft as well as the Polar spacecraft to monitor the region. On 10…
The cusp as a source of magnetospheric particles
Chen, J.; Fritz, T. A.; Walsh, B. M. +1 more
Observations made by a number of satellites have shown that plasma of solar wind/magnetosheath origin enters the high altitude polar cusp creating diamagnetic cavities of large dimensions. The Earth's dipole field can be excluded from this region in a turbulent manner with the magnitude of the field strength reaching close to 0 nT at times. In the…
Observations of a broad and dynamic region of radiation in geospace
Chen, Jiasheng; Lyu, Ling-Hsiao
The solar wind particles can directly access the high-altitude cusp. They could create large diamagnetic cavities with a size of 6RE (Earth radii) in the latitudinal direction and >10RE in the longitudinal direction at an altitude of 7-8RE, and up to 10.5RE in the depth; they could depress the field f…