Photospheric Abundances of Polar Jets on the Sun Observed by Hinode

TL;DR

This study analyzes the elemental abundances of polar jets on the Sun using Hinode observations, finding they have photospheric compositions similar to the fast solar wind, supporting the reconnection jet model.

Contribution

It provides the first detailed abundance measurements of polar jets, linking their composition to the fast solar wind and supporting the reconnection jet model.

Findings

75% of jets have photospheric-like abundances

FIP bias factors range from 0.7 to 1.9

Jets likely contribute to the fast solar wind

Abstract

Many jets are detected at X-ray wavelengths in the Sun's polar regions, and the ejected plasma along the jets has been suggested to contribute mass to the fast solar wind. From in-situ measurements in the magnetosphere, it has been found that the fast solar wind has photospheric abundances while the slow solar wind has coronal abundances. Therefore, we investigated the abundances of polar jets to determine whether they are the same as that of the fast solar wind. For this study, we selected 22 jets in the polar region observed by Hinode/EIS (EUV Imaging Spectrometer) and XRT (X-Ray Telescope) simultaneously on 2007 November 1-3. We calculated the First Ionization Potential (FIP) bias factor from the ratio of the intensity between high (S) and low (Si, Fe) FIP elements using the EIS spectra. The values of the FIP bias factors for the polar jets are around 0.7-1.9, and 75$\%$ of the values are in the range of 0.7-1.5, which indicates that they have photospheric abundances similar to the fast solar wind. The results are consistent with the reconnection jet model where photospheric plasma emerges and is rapidly ejected into the fast wind.