The relationship between plasmapause, solar wind and geomagnetic activity between 2007 and 2011

Abstract

Abstract. Taking advantage of the Cluster satellite mission and especially the observations made by the instrument WHISPER to deduce the electron number density along the orbit of the satellites, we studied the relationships between the plasmapause positions (L PP ) and the following L PP indicators: (a) solar wind coupling functions B z (Z component of the interplanetary magnetic field vector, B, in GSM system), BV (related to the interplanetary electric field; B is the magnitude of the interplanetary magnetic field vector, V is solar wind velocity), and d mp /dt (which combines different physical processes responsible for the magnetospheric activity) and (b) geomagnetic indices Dst, Ap and AE. The analysis is performed separately for three magnetic local time (MLT) sectors (Sector1 -night sector (01:00-07:00 MLT); Sector2 -day sector (07:00-16:00 MLT); Sector3 -evening sector (16:00-01:00 MLT)) and for all MLTs taken together. All L PP indicators suggest the faster plasmapause response in the postmidnight sector. Delays in the plasmapause responses (hereafter time lags) are approximately 2-27 h, always increasing from Sector1 to Sector3. The obtained fits clearly resolve the MLT structures. The variability in the plasmapause is the largest for low values of L PP indicators, especially in Sector2. At low activity levels, L PP exhibits the largest values on the dayside (in Sector2) and the smallest on the postmidnight side (Sector1). Displacements towards larger values on the evening side (Sector3) and towards lower values on the dayside (Sector2) are identified for enhanced magnetic activity. Our results contribute to constraining the physical mechanisms involved in the plasmapause formation and to further study the still not well understood related issues.

The Midlatitude Trough and the Plasmapause in the Nighttime Ionosphere Simultaneously Observed by DEMETER During 2006–2009

“…This study agrees with their result that there is no consistent tendency but complex and/or random between the solar activity and nighttime trough positions. Figures and show that the plasmapause moves toward the equator and pole during the high and low solar activity ranges, respectively, which agrees with that the plasmapause is located quite far from the Earth at about 7.9 R E during the lower solar activity period of 2007–2010 and shrinks to as low as 2.9 R E in the higher solar activity of 2011 reported by Verbanac et al ().…”

Development of a 3‐D Plasmapause Model With a Back‐Propagation Neural Network

“…Generally, all these models were constructed with single-or multiple-parameter fitting. Since the direct driver of the variations in geospace is the external solar wind, the solar wind and interplanetary magnetic field (IMF) parameters were then introduced into the models (e.g., Bandić et al, 2016;Cho et al, 2015;Larsen et al, 2007;Verbanac et al, 2015). Following this scheme, several works have used other geomagnetic indices such as Dst, SYM-H, and AE, to construct models (Moldwin et al, 2002;O'Brien & Moldwin, 2003).…”

MLT Plasmapause Characteristics: Comparison Between THEMIS Observations and Numerical Simulations

“…Relationships between plasmapause positions ( L PP s) and/or solar wind parameters/geomagnetic indices obtained with statistical studies (Bandić et al, ; Carpenter & Anderson, ; Liu et al, ; Moldwin et al, ; O'Brien & Moldwin, ; Verbanac et al, ) have provided the plasmapause shapes for different levels of geomagnetic indices. Many works have also been focused on studying specific events, usually related to geomagnetic storms and, in general, were successful in explaining the observed plasmapause features (e.g., Goldstein, Burch, et al, ; Goldstein, Sandel, et al, ; Pierrard & Cabrera, ; Pierrard et al, ).…”