Solar wind stream interaction regions without sector boundaries

Abstract

During periods of high solar activity when there are many sources of solar wind on the solar disk, a spacecraft occasionally encounters consecutive solar wind streams with the same magnetic polarity. The low‐speed wind in the region of interaction between the two streams exhibits many of the same features as, but has some differences from, the low‐speed wind that includes crossings of the heliospheric current sheet (HCS) where the direction of the heliospheric magnetic field reverses. The non‐HCS slow wind exhibits many of the same small‐scale structures usually associated with the slow wind around the HCS; these include discontinuous stream interfaces and other discontinuities, magnetic holes, and low‐entropy structures. These entropy holes do not appear to have the same origin as the plasma sheets observed near the HCS, however. The helium abundances and heavy ion charge states in the non‐HCS regions are not significantly different from those in HCS‐associated regions. Some of the dynamical properties of the non‐HCS regions differ from those found near the HCS; the regions between leading and trailing stream interfaces have a shorter duration or scale size, greater minimum speed, and lower peak and average densities. No correlation could be found between the non‐HCS slow wind and visible coronal streamers.