Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 35, 1231-1240, 2017
https://doi.org/10.5194/angeo-35-1231-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
Regular paper
13 Nov 2017
High-intensity, long-duration, continuous AE activity events associated with Alfvénic fluctuations in 2003
Alan Prestes, Virginia Klausner, and Arian Ojeda-González Vale do Paraiba University – UNIVAP 12244-000, São José dos Campos, SP, Brazil
Abstract. The interaction between a fast-speed and a low-speed stream causes large-amplitude Alfvénic fluctuations; consequently, the intermittency and the brief intervals of southward magnetic field associated with Alfvén waves may cause high levels of AE activity, the so-called high-intensity, long-duration, continuous AE activity (HILDCAA). In this article, the 4 h windowed Pearson cross-correlation (4WPCC) between the solar wind velocity and the interplanetary magnetic field (IMF) components is performed in order to confirm that the less strict HILDCAA (HILDCAAs*) events include a larger number of Alfvén waves than the HILDCAA events, once HILDCAAs disregard part of the phenomenon. Actually, a HILDCAA event is entirely contained within a HILDCAA* event. However, the opposite is not necessarily true. This article provides a new insight, since the increase of Alfvén waves results in an increase of auroral electrojet activity; consequently, it can cause HILDCAAs* events. Another important aspect of this article is that the superposed epoch analysis (SEA) results reaffirm that the HILDCAAs* are associated with high-speed solar streams (HSSs), and also the HILDCAAs* present the same physical characteristics of the traditional HILDCAA events.

Citation: Prestes, A., Klausner, V., and Ojeda-González, A.: High-intensity, long-duration, continuous AE activity events associated with Alfvénic fluctuations in 2003, Ann. Geophys., 35, 1231-1240, https://doi.org/10.5194/angeo-35-1231-2017, 2017.
Publications Copernicus
Download
Share