Storm time enhancements of 630.0 nm airglow associated with polar cap patches

Abstract

We examined the brightness of 630.0 nm airglow, I630, associated with polar cap patches observed during a magnetic storm that occurred on 22 January 2012. Brightness was measured using an all‐sky imager (ASI) located at Longyearbyen, Svalbard. The observed I630 was compared with the F region electron density observed by the European Incoherent Scatter Svalbard Radar (ESR). The I630 was positively correlated with the F2 layer peak electron density, NmF2, and inversely correlated with the altitude of the F2layer peak electron density, hmF2, as expected from the known relationship between these parameters. To estimate the altitude of the peak emission of the airglow, we performed model calculations of the volume emission rate, V630, under quiet and disturbed conditions, using Mass Spectrometer Incoherent Scatter modeled neutral gas profiles and the electron density profile obtained from the ESR data. In order to validate the V630 calculation, I630 was calculated by integrating the V630 along altitude and then compared with the ASI‐observed I630. During the observation periods the measured brightness frequently exceeded the calculated I630; we infer that in most cases, low‐energy particle precipitation is responsible for the extra brightness. However, when there was less particle precipitation, the observed values were in good agreement with the calculated values. Under the magnetically disturbed conditions during our observations, the model calculation showed that the altitude of V630 peak increases, the thickness of the emission layer increases, and patch brightness increases.

Three different types of electric field disturbances affecting equatorial ionosphere during a long‐duration prompt penetration event

“…These authors recently presented 630.0 nm airglow intensity variations over Svalbard associated with polar cap patches during 1800–2400 UT on 22 January 2012. Although not reported by Sakai et al [], ∼40 min periodicity can be noticed in the observed 630.0 nm airglow intensity variation during 1800–2030 UT on this night. Therefore, it is clear that the ∼40 min fluctuation in IEF y has a global effect on this particular night and strengthens the argument for the DP2 origin of the fluctuations with similar periodicity observed over the equatorial region during midnight hours.…”

Analysis of close conjunctions between dayside polar cap airglow patches and flow channels by all-sky imager and DMSP

“…Similarly, we map blue (427.8 nm) emission snapshots to 110 km. These are typical mapping altitudes at these wavelengths (Gulledge et al 1968;Axelsson et al 2014;Sakai et al 2014). However, there are some errors associated with this mapping.…”

“…However, there are some errors associated with this mapping. To estimate the errors, we use intensity profiles for airglow red emission presented by Sakai et al (2014), which showed that the airglow emission of polar cap patches is peaked at ~280 km altitude during disturbed time. The errors from the 230 km altitude mapping can be estimated as:…”

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

“…As shown in Taguchi et al (2012), the 630.0 nm (red) line data from this EMCCD camera can provide detailed information about the dynamic features of moving cusp auroral structures. The high sensitivity of this camera is also very effective for identifying the structure of polar cap patches (Hosokawa et al 2013a(Hosokawa et al , 2013bSakai et al 2014). Thus, in the current study, we used 630.0 nm wavelength images.…”