Pc1-2 auroral pulsations

Abstract

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 π/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. © 2012. American Geophysical Union. All Rights Reserved.