ALMA and IRIS Observations of the Solar Chromosphere I: an On-Disk Type II Spicule

TL;DR

This paper combines ALMA and IRIS observations with advanced modeling to detect and analyze an on-disk chromospheric spicule, revealing its multithermal properties and providing new insights into solar chromosphere dynamics.

Contribution

It introduces simultaneous multi-instrument observations and a comprehensive 2.5D radiative MHD model to study on-disk spicules with non-equilibrium ionization effects.

Findings

Detection of an on-disk chromospheric spicule with ALMA.

Confirmation of the multithermal nature of the spicule.

Insights into the structure of the solar chromosphere.

Abstract

We present observations of the solar chromosphere obtained simultaneously with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Interface Region Imaging Spectrograph (IRIS). The observatories targeted a chromospheric plage region of which the spatial distribution (split between strongly and weakly magnetized regions) allowed the study of linear-like structures in isolation, free of contamination from background emission. Using these observations in conjunction with a radiative magnetohydrodynamic 2.5D model covering the upper convection zone all the way to the corona that considers non-equilibrium ionization effects, we report the detection of an on-disk chromospheric spicule with ALMA and confirm its multithermal nature.