Pc1–2 auroral pulsations

Abstract

[1] By observations at Lovozero station (64.3 N, 114.3 E CGM coordinates), we have investigated two events of auroral pulsations of Pc1-2 type with periods in the range 2.5-7 s accompanied by similar geomagnetic pulsations. Luminous variations in different parts of the sky were found by photometric measurements of the frames of all-sky camera, which was operated at the rate of one frame per second. The pulsations under study are associated with the diffuse aurora. For the event with 7 s period, a phase relationship between auroral and magnetic pulsations is as follows: the luminosity bursts are coincident with positive half periods in the Z component and negative ones in the D component, while positive peaks in the H component lag behind the luminous peaks by about p/2. For the event with 2.5 s period, this relationship appears different. Within one of 10-min intervals, Pc2 pulsations observed in both magnetic field and aurora were superposed by regular Pc4 pulsations of 1-min period. For these, the luminosity bursts corresponded to negative half periods in the Z component. A connection between auroral and magnetic pulsations is discussed.

Global characteristics of Pc1 magnetic pulsations during solar cycle 23 deduced from CHAMP data

“…Fraser et al, 1996;Nomura et al, 2012) and in the auroral region (e.g. Roldugin et al, 2013). However, Pc1 pulsations appear also in regions of open geomagnetic field lines, such as cusp/mantle (e.g.…”

Geophysicochemical model of an ionospheric auroral gyroscope

“…Foat et al [] have found that the frequency of quasi‐periodic modulation (~0.05–0.1 Hz) was observed in the X‐rays flux. Furthermore, all of the X‐rays burst were accompanied by ~0.2 Hz increase in the first mode of SR frequency [ Roldugin et al , ]. This frequency is the same for the polhodic cone ω /2 π (1).…”

“…The bipolar, converging or diverging, perpendicular electric fields and U‐shaped potential structures are probably related with the parallel electric fields [ Mozer and Kletzing , ]. The geophysical importance of Pc1 pulsations to the auroral region is their close connection to proton precipitation [ Roldugin et al , ] and traveling convection vortices (TCV) [ Engebretson et al , ]. As a result of upward FAC, the truncated cone appears in the polar aurora region with the axis acting as an axis of symmetry that is referred to the electron cavity aurora (ECA) and performs in the vertical direction with shear Alfvén waves (Figure ).…”

A human source for ELF magnetic perturbations

“…In general, human beings experience a variety of physiological and medical effects that can be traced to both geophysical and electric power sources. Among these varied geophysical sources one finds Schumann resonances (Fullerkrug, 2005;Galejs, 1965), diurnal geomagnetic rhythms (Chapman, 1918;Liboff, 2014a), Pc1 magnetospheric oscillations (pearls) (Guglielmi and Kangas, 2007;Roldugin et al, 2013;Rusov et al, 2012) and, most notably, solar storm activity (Liboff, 2014b). The daily swing in the geomagnetic intensity is approximately 20-50 nT (Liboff, 2014a), but deviations can be up to ten times greater during periods of increased solar activity.…”