Cusp observations of high‐ and low‐latitude reconnection for northward IMF: An alternate view

During high solar wind dynamic pressure, northward interplanetary magnetic field (IMF) intervals, the POLAR/TIMAS instrument observes angular distribution functions, that have been interpreted in terms of reconnection, below the latitude of the cusp, of nearly parallel magnetic field lines from the magnetosheath with those in the magnetosphere. If true, this process would lead to erosion of the dayside magnetosphere by northward IMF, a process not consistent with the observed control by IMF Bz of the location of the dayside magnetopause, of the polar cusp, or of geomagnetic activity. However, we note that the TIMAS observations do not require such an interpretation and that a simpler interpretation exists, consistent with the current paradigm of IMF effects on the magnetosphere.