The connection of solar wind parameters with microwave and UV emission of coronal hole atmosphere

TL;DR

This study investigates the relationship between solar wind parameters and emissions in UV and microwave spectra from coronal holes, revealing correlations and suggesting multiple mechanisms for solar wind acceleration.

Contribution

It identifies correlations between solar wind velocity and emissions at different atmospheric levels, proposing multiple acceleration mechanisms.

Findings

Increase in solar wind velocity correlates with UV flux decrease.

Connection established between microwave emissions and solar wind velocity.

Evidence suggests two different solar wind acceleration mechanisms.

Abstract

This paper presents results of comparison between observations of coronal holes in the UV (SOHO EIT) and microwave emission (17, 5.7 GHz, 327 and 150.9 MHz, NoRH, SSRT and Nancy radioheliographs), and solar wind parameters, according to the ACE spacecraft data over the period 12 March--31 May 2007. Increase in the solar wind velocity up to ~600 km/s was found to correlate with decrease in the UV flux in the central parts of the solar disk. The connection between parameters of the microwave emission at three different solar atmosphere levels and the solar wind velocity near the Earth's orbit was determined. This connection suggests existence of common mechanisms of solar wind acceleration from chromospheric altitudes to the upper corona. We also suppose existence of two different mechanisms of the solar wind acceleration at altitudes of less and more than one solar radius.