Multispacecraft observations of sudden impulses in the magnetotail caused by solar wind pressure discontinuities: Wind and IMP 8

Cluster observations of sudden impulses in the magnetotail caused by interplanetary shocks and pressure increases

“…Especially for the southward interplanetary magnetic field (IMF), pressure pulses cause almost immediate and global enhancements in ionospheric currents and auroral precipitation, see (Zhou and Tsurutani, 1999;Zesta et al, 2000;Boudouridis et al, 2003;Meurant et al, 2003). In the tail lobes, sudden increases in the magnetic field have been observed on time scales from a few to ten minutes, see (Sugiura et al, 1968;Kawano et al, 1992;Collier et al, 1998;Kim et al, 2004).…”

“…What is actually relevant for magnetopause compression is the pressure profile in the magnetosheath. However, as discussed in Collier et al (1998), the pressure discontinuities in the solar wind are transmitted through the bow shock to form similar structures in the magnetosheath.…”

“…Two mechanisms have been suggested as the cause of the tail lobe SIs: 1) The transfer of magnetic flux from the dayside to the tail by magnetohydrodynamic (MHD) waves resulting from the sudden enhancement of solar wind pressure on the front of the magnetosphere (Sugiura et al, 1968); 2) Compression of the magnetotail by magnetosheath pressure increases, see (Kawano et al, 1992;Collier et al, 1998). In the first scenario the disturbance propagates at the Alfvén speed.…”

“…During the event on 6 November 2001 the magnetopause was compressed past Cluster. We applied the 2-D Cartesian model developed by Collier et al (1998) in which a vacuum uniform tail lobe magnetic field is compressed by a step-like pressure increase. The model underestimates the compression of the magnetic field, but it fits the magnetic field maximum variance component well.…”

Automatic Detection Algorithm of Dynamic Pressure Pulses in the Solar Wind

“…Many papers were devoted to studying the responses of the main plasma regions in the magnetosphere and ionosphere to large positive DPPs usually associated with strong IP shocks or other discontinuities. The magnetospheric compression resulting from a large pressure front may involve sudden changes of not only the magnetopause current system but also the tail current and reconnection-related field-aligned currents (Zesta et al 2000, p. 127), which in sequence cause a sudden increase in the ground geomagnetic field (Russell et al 1994;Liou et al 2004), disturbances in the magnetic field at the geosynchronous orbit (Sanny et al 2002;Wing et al 2002;Wang et al 2007), and disturbances in the magnetic field at the tail lobe (Fairfield & Jones 1996;Ostapenko & Maltsev 1998;Collier et al 1998;Kim et al 2004). It can trigger the sudden enhancement of the flux of the energetic particles nearly simultaneously in both the dayside and nightside at the geosynchronous orbit .…”