Connecting the Low to High Corona: Propagating Disturbances as Tracers of the Near-Sun Solar Wind

We revisit a quiet 14 day period of solar minimum during 2008 January and track substreamer propagating disturbances (PDs) from low heights in STEREO/EUVI to the extended corona through STEREO/COR1 and into STEREO/COR2 along nonradial paths that trace the structure of the underlying streamers. Using our recently developed method for generating nonradial height-time profiles of outward PDs (OPDs) and inward PDs (IPDs), we obtained their velocities along the radial and position angle directions. Our analysis of 417 unique OPDs revealed two classes: slow and fast OPDs. Slow OPDs form preferentially at ≈1.6 R _⊙ closer to the streamer boundaries, with asymmetric occurrence rates, and show speeds of 16.4 − 8.4 + 26.6 km s − 1 at 1.5 R _⊙ and accelerate up to 200.1 − 57.9 + 71.1 km s − 1 at 7.5 R _⊙. Fast OPDs form preferentially at ≈1.6 R _⊙ and at ≈3.0 R _⊙ both at the streamer boundaries and slightly more often within them. They show speeds of 87.8 − 24.8 + 59.1 km s − 1 at 1.5 R _⊙ up to 197.8 − 46.7 + 61.8 km s − 1 at 7.5 R _⊙. IPDs are observed forming at ≈1.8 R _⊙ with speeds of tens of kilometers per second, mostly concentrated in the aftermath of a coronal mass ejection eruption. We present an example in which we show that periodic brightness variations related to OPDs remained in the range of 98 to 128 minutes, down to ≈2.0 R _⊙, well within the field of view of COR1. The velocity profiles of slow OPDs for a heliocentric height below 3.0 R _⊙ show good agreement with speeds more closely related to the bulk solar wind obtained via interplanetary scintillation.