Observational evidence for the associated formation of blobs and raining inflows in the solar Corona

TL;DR

This study provides observational evidence linking the formation of solar wind blobs with raining inflows in the solar corona, supporting the idea that magnetic reconnection above helmet streamers releases these structures.

Contribution

First direct observational association between blobs and raining inflows, clarifying their formation region and mechanism in the solar corona.

Findings

Blobs are released above helmet streamers during magnetic reconnection.

Raining inflows are observed concurrently with blob release.

Blob formation is supported as a magnetic reconnection process.

Abstract

The origin of the slow solar wind is still a topic of much debate. The continual emergence of small transient structures from helmet streamers is thought to constitute one of the main sources of the slow wind. Determining the height at which these transients are released is an important factor in determining the conditions under which the slow solar wind forms. To this end, we have carried out a multipoint analysis of small transient structures released from a north-south tilted helmet streamer into the slow solar wind over a broad range of position angles during Carrington Rotation 2137. Combining the remote-sensing observations taken by the Solar-TErrestrial RElations Observatory (STEREO) mission with coronagraphic observations from the Solar and Heliospheric Observatory (SoHO) spacecraft, we show that the release of such small transient structures (often called blobs), which subsequently move away from the Sun, is associated with the concomitant formation of transient structures collapsing back towards the Sun; the latter have been referred to by previous authors as raining inflows. This is the first direct association between outflowing blobs and raining inflows, which locates the formation of blobs above the helmet streamers and gives strong support that the blobs are released by magnetic reconnection.