# The origin of slow Alfv\'enic solar wind at solar minimum

## TL;DR

This paper investigates the kinetic properties of slow Alfvénic solar wind at 0.35 AU, providing evidence that it originates from coronal holes and shares many characteristics with fast solar wind.

## Contribution

It offers new insights into the kinetic features of slow Alfvénic wind and links its origin to coronal hole magnetic field lines, expanding understanding of solar wind sources.

## Key findings

- High alpha particle abundances and differential streaming in slow Alfvénic wind
- Presence of strong proton beams and large alpha-to-proton temperature ratios
- Differences in speed, mass flux, and electron temperature explained by magnetic field geometry

## Abstract

Although the origins of slow solar wind are unclear, there is increasing evidence that at least some of it is released in a steady state on over-expanded coronal hole magnetic field lines. This type of slow wind has similar properties to the fast solar wind, including a high degree of Alfv\'enicity. In this study a combination of proton, alpha particle, and electron measurements are used to investigate the kinetic properties of a single interval of slow Alfv\'enic wind at 0.35 AU. It is shown that this slow Alfv\'enic interval is characterised by high alpha particle abundances, pronounced alpha-proton differential streaming, strong proton beams, and large alpha to proton temperature ratios. These are all features observed consistently in the fast solar wind, adding evidence that at least some Alfv\'enic slow solar wind also originates in coronal holes. Observed differences between speed, mass flux, and electron temperature between slow Alfv\'enic and fast winds are explained by differing magnetic field geometry in the lower corona.