Magnetopause location under extreme solar wind conditions

Abstract

Abstract.During the solar wind dynamic pressure enhancement, around 0200 UT on January 11, 1997, at the end of the January 6-11 magnetic cloud event, the magnetopause was pushed inside geosynchronous orbit. The LANL 1994-084 and G MS 4 geosynchronous satellites crossed the magnetopause and moved into the magnetosheath. Also, the Geotail satellite was in the magnetosheath while the Interball i satellite observed magnetopause crossings. This event provides an excellent opportunity to test and validate the prediction capabilities and accuracy of existing models of the magnetopause location for producing space weather forecasts. In this paper, we compare predictions of two models: the Petrinec and Russell

Response of neutral atom emissions in the low‐latitude and high‐latitude magnetosheath direction to the magnetopause motion under extreme solar wind conditions

“…[12] A large negative B z , as well as increasing of the dynamic pressure, is a controlling parameter for the reduction of the dayside magnetopause dimension [Roelof and Sibeck, 1993;Petrinec and Russell, 1996;Shue et al, 1998, and references therein]. The above connection of the LENA emission to both the solar wind dynamic pressure and IMF B z indicates that the reduction of the dayside magnetopause dimension is a major controlling parameter for the LENA emission enhancements.…”

“…While these types of models have successfully predicted the motion of the magnetopause near the equatorial plane even for extreme solar wind situations [Shue et al, 1998], it is still unclear to what extent the validity of the models, which assume cylindrical symmetry around the aberrated Sun-Earth direction, can be extended to the X-Z meridian structure. In this meridian the magnetopause has a cusp indentation, and the characteristics of this indentation, in particular, the solar wind control of the location, need to be clarified for a full understanding of the dynamic features of the magnetopause.…”

Asymmetry of magnetosheath flows and magnetopause shape during low Alfvén Mach number solar wind

“…The statistical data ordering is essentially based on the magnetosheath-interplanetary medium (MIPM) reference frame developed by Verigin et al [2006]. This consists of a spatial superposed analysis which orders spacecraft data from a given time and location relative to models of the magnetopause [Shue et al, 1997[Shue et al, , 1998] and bow shock positions [Verigin et al, 2006]. Using appropriately lagged (using Cluster and ACE spacecraft positions and the measured solar wind velocity at ACE) ACE data as inputs to the models, a fractional position of Cluster in the magnetosheath, relative to the model boundaries (between 0 and 1), is obtained along the direction of the spacecraft position vector (see also Nĕmecek et al [2000Nĕmecek et al [ , 2003 for similar procedures).…”

“…Statistical distribution of the magnetosheath ion speed measured at Cluster normalized to the appropriately lagged ion speed measured at ACE for each 5 min data averages; a color palette of |V SHEATH |/|V SW | is given in the top right corner. The statistical data ordering is based on the magnetosheath-interplanetary medium (MIPM) reference frame developed by Verigin et al [2006], using models of the magnetopause [Shue et al, 1997[Shue et al, , 1998] and bow shock positions [Verigin et al, 2006] with appropriately lagged ACE data as inputs. Each data point is assigned an X and R (R = √(Y 2 + Z 2 )) position in the normalized reference frame.…”

“…[23] In order to highlight a relative change in magnetopause shape, the observed magnetopause distances from our crossings lists are then compared to the Shue et al [1997Shue et al [ , 1998] model for the prevailing solar wind conditions (with IMF B Z and dynamic pressure as input). We here use the difference (R REAL À R SHUE ) between the observed and Figure 5.…”