Influence of interplanetary magnetic field and solar wind on auroral brightness in different regions

Abstract

[1] By integrating and averaging the auroral brightness from Polar Ultraviolet Imager auroral images, which have the whole auroral ovals, and combining the observation data of interplanetary magnetic field (IMF) and solar wind from NASA Operating Missions as a Node on the Internet (OMNI), we investigate the influence of IMF and solar wind on auroral activities, and analyze the separate roles of the solar wind dynamic pressure, density, and velocity on aurora, respectively. We statistically analyze the relations between the interplanetary conditions and the auroral brightness in dawnside, dayside, duskside, and nightside. It is found that the three components of the IMF have different effects on the auroral brightness in the different regions. Different from the nightside auroral brightness, the dawnside, dayside, and duskside auroral brightness are affected by the IMF B x , and B y components more significantly. The IMF B x and B y components have different effects on these three regional auroral brightness under the opposite polarities of the IMF B z . As expected, the nightside aurora is mainly affected by the IMF B z , and under southward IMF, the larger the |B z |, the brighter the nightside aurora. The IMF B x and B y components have no visible effects. On the other hand, it is also found that the aurora is not intensified singly with the increase of the solar wind dynamic pressure: when only the dynamic pressure is high, but the solar wind velocity is not very fast, the aurora will not necessarily be intensified significantly. These results can be used to qualitatively predict the auroral activities in different regions for various interplanetary conditions.

Investigating the particle precipitation of a moving cusp aurora using simultaneous observations from the ground and space

“…A negative B X when B Z < 0 may be a relatively favorable condition for stronger auroral emission on the dayside (Yang et al 2013). The solar wind plasma density N sw was approximately 5 cm −3 during that interval (Figure 2d).…”

Variation and modeling of ultraviolet auroral oval boundaries associated with interplanetary and geomagnetic parameters

“…Different IMF conditions make the auroral oval drift to different directions [ Meng , ; Cowley et al ., ; Liou et al ., ]. The solar wind, especially the solar wind dynamic pressure, can affect significantly the Earth's magnetic field and the magnetospheric topology, thereby affecting the aurora [ Lyons , ; Lee et al ., ; Yang et al ., ]. Newell et al .…”

Magnetospheric vortices and their global effect after a solar wind dynamic pressure decrease

“…Solar wind energy can be transferred into the magnetosphere and ionosphere system through solar wind pressure-pulse buffeting of the magnetosphere. Positive solar wind dynamic pressure pulses can induce various effects inside the magnetosphere, such as generation of ULF waves [e.g., Kaufmann and Walker, 1974;Nopper et al, 1982;Wedeken et al, 1984;Cahill et al, 1990;Sarris et al, 2010;Shi et al, 2013], modulation of energetic particles [e.g., Lessard et al, 1999;Zong et al, 2007], induction of vortices [e.g., Glassmeier et al, 1989Glassmeier et al, , 1992Samsonov et al, 2010;Wang et al, 2010;Samsonov and Sibeck, 2013;Shi et al, 2014], enhancement of auroral activities [e.g., Zhou and Tsurutani, 1999;Boudouridis et al, 2003;Meurant et al, 2003;Yang et al, 2011Yang et al, , 2013, and adjustment of geosynchronous magnetic field variations [e.g., Wing and Sibeck, 1997;Wing et al, 2002;Lee and Lyons, 2004;Borodkova et al, 2005;Wang et al, 2007]. Sibeck [1990] proposed a model of the interaction between solar wind dynamic pressure pulses and the magnetosphere in which solar wind compression on the magnetopause produces a vortex in the magnetosphere near the magnetopause.…”