The Effects of Solar Wind Dynamic Pressure Changes on the Substorm Auroras and Energetic Electron Injections on 24 August 2005

Abstract

After the passage of an interplanetary (IP) shock at 06:13 UT on 24 August 2005, the enhancement (>6 nPa) of solar wind dynamic pressure and the southward turning of interplanetary magnetic field (IMF) cause the earthward movement of dayside magnetopause and the drift loss of energetic particles near geosynchronous orbit. The persistent electron drift loss makes the geosynchronous satellites cannot observe the substorm electron injection phenomenon during the two substorm expansion phases (06:57–07:39 UT) on that day. Behind the IP shock, the fluctuations (~0.5–3 nPa) of solar wind dynamic pressure not only alter the dayside auroral brightness but also cause the entire auroral oval to swing in the day‐night direction. However, there is no Pi2 pulsation in the nightside auroral oval during the substorm growth phase from 06:13 to 06:57 UT. During the subsequent two substorm expansion phases, the substorm expansion activities cause the nightside aurora oval brightening from substorm onset site to higher latitudes, and meanwhile, the enhancement (decline) of solar wind dynamic pressure makes the nightside auroral oval move toward the magnetic equator (the magnetic pole). These observations demonstrate that solar wind dynamic pressure changes and substorm expansion activities can jointly control the luminosity and location of the nightside auroral oval when the internal and external disturbances occur simultaneously. During the impact of a strong IP shock, the earthward movement of dayside magnetopause probably causes the disappearance of the substorm electron injections near geosynchronous orbit.

Evolution of Dynamical Complexities in Geospace as Captured by Dst Over Four Solar Cycles 1964–2008.

“…The enhancement of solar wind dynamic pressure and the southward turning of interplanetary magnetic field (IMF) often cause many intense disturbances in geospace (Kamide & Chian, 2007;L. Y. Li & Wang, 2018).…”

Effects of Solar Wind Plasma Flow and Interplanetary Magnetic Field on the Spatial Structure of Earth's Radiation Belts

“…Moreover, other disturbances are probably triggered inside the magnetosphere during the large northward IMFs and high solar wind densities/pressures, such as intense storms or substorms and associated plasma waves (Cao et al, ; Li et al, ; Li, Yu, et al, ). When the internal and external disturbances occur at the same time (Li & Wang, ), they could jointly control the spatial distribution of the radiation belt electrons.…”

“…However, the effects of IMF B z on the Earth's magnetosphere and radiation belts are naturally efficient (Cao et al, 2013;Dong et al, 2014;Li et al, 2011Li et al, , 2013). On the one hand, a large southward IMF (B z < 0 nT) can reduce the geocentric distance of dayside magnetopause (Shue et al, 1998) and thus triggers the electron drift loss at high-L shells (Li & Wang, 2018). On the other hand, the southward IMFs can cause intense storms and substorms and thus inject more "seed electrons" into the low-L region (Li, Cao, et al, 2006).…”

“…During the passage of CMEs or CIRs, the electric and magnetic fields in Earth's magnetosphere are remarkably changed (Li et al, , ; Zhang et al, ). The change in solar wind dynamic pressure also modifies the intensity of plasma waves (Li et al, ; Li et al, ; Yu et al, ; Zhou et al, ), auroral brightness, and location (Li & Wang, ).…”

Dynamics for geomagnetic pulsations, field-aligned currents, and airglow at mid-latitudes within substorm activations during superstorms

“…When studying the main objects of space weather and of geodynamics -magnetospheric substorms and storms -one observes geomagnetic pulsations of various types, as well as auroras with the intensity exceeding 100 kR. These events are accompanied by an increase in electric fields and currents in the ionosphere of the auroral zone that, during superstorms (sometimes observed strongest storms), can spread to the mid latitudes [Troitskaya, Gul'elmi, 1967;Pudovkin et al, 1976;Tinsley et al, 1986;Brunelli, 1988;Rassoul et al, 1993;Kangas et al, 1998;Mikhalev et al, 2004;Zverev et al, 2012;Leonovich et al, 2013;Li, Wang, 2018]. During the 2003 Nov 20 storm (one of the strongest), from the mid-latitude geophysical observatories located near Irkutsk (CGM: 47.3° Ф, 177° Λ) in the post-midnight MLT sector, there recorded shortperiod Pi1B/Pi1С pulsations, and disturbances of optical emissions in the 557.7 nm and 630.0 nm atomic oxygen [OI] lines, as well as in 391.4 nm ionized nitrogen molecular band, with record-breaking intensity values [Mishin et al, 2018].…”