Nighttime Pc3 pulsations: MM100 and MAGDAS observations

Abstract

Abstract In this paper, we present a statistical and case analysis of nighttime Pc3 pulsations observed from middle to equatorial latitudes during the year 2003. We found two groups of nighttime Pc3 pulsations. Pc3s of the first group are in fact the nightside counterpart of morning Pc3 pulsations with large azimuthal scales slowly attenuating toward midnight. Such night signatures of morning Pc3 waves are observed during the periods of fast solar wind ( $$V>500\,\hbox {km/s}$$ V > 500 km/s ). The second type is the locally generated night Pc3 pulsations. They can be observed under moderate solar wind velocities. Maximal occurrence rates and amplitudes for these pulsations are recorded at middle geomagnetic latitudes near the local magnetic midnight. Probably, they are associated with auroral activations or local non-substorm bursty processes. Graphical abstract An example of a nighttime Pc3 pulsation Graphical abstract Empirical probability density function of the solar wind speed for the intervals with the two types of night Pc3 pulsations and for all the intervals analyzed.

Keywords

• Geomagnetic pulsations
• Ionosphere
• Magnetosphere