Spectral and photometric characteristics of mid-latitude auroras during the magnetic storm of March 17, 2015

Abstract

We study the spatiotemporal dynamics of mid-latitude aurora from observations in the south of Eastern Siberia during St. Patrick’s severe geomagnetic storm on March 17, 2015. We perform a morphological analysis of characteristics of the observed auroras. A preliminary conclusion is drawn that the analyzed event is the result of the manifestation of mid-latitude auroras of two types (type “d” and SAR arc) and ordinary aurora observed at the northern horizon. The maximum intensity of the dominant emission [OI] at 630.0 nm (~14 kR) allows this mid-latitude aurora to be attributed to the extreme auroras occurring in mid-latitudes, which is second only to the November 20, 2003 superstorm (~19 kR).

Mid-Latitude Aurora in Solar Cycles 23–24 From Observations in the South of Eastern Siberia

“…Note that in the diffuse aurora there is practically no aurora in the N 2 + (1NG) bands [Starkov, 2000]. At the same time, some MSs analyzed in this paper also exhibit the 520 nm [NI] emission (on September 26, 2011 andMarch 17, 2015) and the 391.4 and 586.7 nm N 2 + (1NG) bands (on November 20, 2003 andMarch 17, 2015) [Mikhalev et al, 2004[Mikhalev et al, , 2018Mishin et al, 2018].…”

“…As derived from GPhO observations, only four events have been classed with SAR arcs: March 25, 1991, April 7, 2000, March 31, 2001[Mikhalev et al, 2005, and March 17, 2015 [Mikhalev et al, 2018].…”

“…Figure 6 shows images in the 630.0 nm emission taken by the all-sky camera KEO at different times compared to the 630.0 nm emission dynamics obtained from patrol spectrograph data [Mikhalev et al, 2018]. The recorded SAR arc moved southward with a mean velocity of ~20 m/s (calculated for the height of ~400 km).…”

“…"Beautiful dark-red structures" are observed at heights 300-400 km [Akasofu, 1966]. Figure 7 displays images of the northern part of the sky obtained from MA observations during the September 26, 2011 andMarch 17, 2015 MSs at different geomagnetic activity levels. We can observe the presence of extended regions with dominant red shades caused by predominance of the 630.0 nm atomic oxygen red emission intensity over the total intensity of all other emissions and continuum in the visible spectrum of MA.…”

Mid-Latitude Aurora in Solar Cycles 23–24 From Observations in the South of Eastern Siberia

“…и полос N 2 + (1NG) 391.4 и 586.7 нм (20 ноября 2003 г. и 17 марта 2015 г.) [Михалев и др., 2004, 2018Mishin et al, 2018].…”