Gone With The Wind

Solar weather has become increasingly important as scientists and spacecraft extend their reach further into the universe. Solar wind impacts the Earth and our satellites every day, but it is not completely understood. For example, the origin of the slow solar wind has been debated for many years. One theory states that the slow wind occurs in areas with a high radial expansion factor [Wang et al., 1996], while another theory contends that it occurs from magnetic reconnection along boundaries of a web of coronal hole corridors [Antiochos et al., 2011]. Both of these theories are compelling and can describe all the observed large-scale characteristics of the slow solar wind, but neither has been tested on smaller scales. We present a case study where we relate in-situ data at Earth to imaging data at the Sun of a pseudo-streamer observed at Earth on August 9^th 2008 [N. U. Cooker et al., 2014]. Pseudo-streamers are a particular type of slow solar wind that does not occur near the heliospheric current sheet (HCS). Since some theories rely on the HCS to explain the behavior of the slow wind, the pseudo-streamer is of particular interest. This streamer was analyzed for periodic density structures that may be associated with the slow solar wind. Density structures were identified using ACE and WIND’s in-situ data and analyzed in STEREO Ahead’s Heliospheric Imager 1(HI1) field of view. Spectral analysis was performed on both in-situ and optical data. Results showed definite periodic structures in the in-situ data and that the solar wind with the periodic structures did not come from near the HCS. The exact stream of solar wind that produced the periodic structures at the Sun is still in question, but the fact that the wind does not originate from the HCS compels us to continue searching for how these structures were formed.