Modeling of Earth's bow shock: Applications

Abstract

[1] Shock-crossing data obtained from spacecraft are used to test the shock location models derived by Chapman and Cairns [2003]. Three sets of data are considered: (1) ISEE 1 for 24-25 September 1987, (2) Wind, Geotail, IMP 8, and Interball for the intervals 26-27 April and 10-13 May 1999, and (3) IMP 8, Geotail, Magion-4, and Cluster during the period 1973-2003 from the bow shock database (available at http:// nssdc.gsfc.nasa.gov/ftphelper/bowshock.html). Derived from MHD simulations, the two shock models are for angles q IMF = 45°and 90°between the upstream magnetic field B IMF and solar wind velocity v sw . These models have azimuthal asymmetries, and they depend explicitly on the upstream Mach number M A and ram pressure P ram . We also test Cairns et al. 's [1995] rotationally symmetric shock model. The new models perform better on average than the rotationally symmetric model, providing some evidence and support for the shock's shape being strongly dependent upon M A and q IMF . We also compare our analyses here with model/spacecraft comparisons performed by Merka et al. [2003a] and discuss the importance of filtering on the model predictions.

Foreshock Properties at Typical and Enhanced Interplanetary Magnetic Field Strengths: Results From Hybrid‐Vlasov Simulations

“…The bow shock shape and position are similar in both runs, despite the fact that M A changes by a factor of 2. Previous works, based on magnetohydrodynamic (MHD) theory (Cairns & Grabbe, ) and simulations (Chapman & Cairns, ), have predicted that the bow shock position becomes less sensitive to changes in M A when Θ Bn tends toward 0, and lower M A values have to be reached before the sunward retreat of the bow shock is observed. The similar bow shocks in our runs are thus due to the quasi‐radial orientation of the IMF accompanied by rather high M A values.…”

On increasing accuracy of bow shock shape and position predictions

“…[16] and Figure 3). However, permanent variations of the solar wind/IMF conditions cause that the bow shock wave is not static relative to Earth.…”

Nowcasting and forecasting of the magnetopause and bow shock—A status update

“…[]. The bow shock location, 3‐D shape and characteristics, and its dependences on the solar wind parameters and IMF have recently been studied using MHD and other numerical models [e.g., De Sterck and Poedts , ; De Sterck et al ., ; Chapman and Cairns , , ; Chapman et al ., ; Hu et al ., ; Hu et al ., ; Wang et al ., , ]. Nykyri [] used a global MHD model for studying the impact of magnetosheath plasma properties on the Kelvin‐Helmholtz instability (KHI) during Parker‐Spiral and ortho‐Parker‐Spiral IMF orientations and for various upstream solar wind plasma conditions.…”