# Interchange reconnection associated with a confined filament eruption: Implications for the source of transient cold-dense plasma in solar winds

## TL;DR

This study links interchange reconnection during a confined filament eruption to the release of cold-dense plasma, suggesting a source for such plasma in the solar wind, with detailed observations of magnetic field changes and plasma flows.

## Contribution

It provides observational evidence of interchange reconnection associated with a confined filament eruption contributing to cold-dense plasma in the solar wind.

## Key findings

- Interchange reconnection occurred during the filament eruption.
- Blob-like plasma was released along open magnetic field lines.
- The eruption was associated with a puff-like CME and magnetic field shifts.

## Abstract

The cold-dense plasma is occasionally detected in the solar wind with in situ data, but the source of the cold-dense plasma remains illusive. Interchange reconnections (IRs) between closed fields and nearby open fields are well known to contribute to the formation of solar winds. We present a confined filament eruption associated with a puff-like coronal mass ejection (CME) on 2014 December 24. The filament underwent successive activations and finally erupted, due to continuous magnetic flux cancellations and emergences. The confined erupting filament showed a clear untwist motion, and most of the filament material fell back. During the eruption, some tiny blobs escaped from the confined filament body, along newly-formed open field lines rooted around the south end of the filament, and some bright plasma flowed from the north end of the filament to remote sites at nearby open fields. The newly-formed open field lines shifted southward with multiple branches. The puff-like CME also showed multiple bright fronts and a clear southward shift. All the results indicate an intermittent IR existed between closed fields of the confined erupting filament and nearby open fields, which released a portion of filament material (blobs) to form the puff-like CME. We suggest that the IR provides a possible source of cold-dense plasma in the solar wind.