# First ALMA Observation of a Solar Plasmoid Ejection from an X-ray Bright Point

## TL;DR

This study presents the first ALMA observation of a solar plasmoid ejection from an X-ray bright point, combining radio, EUV, and X-ray data to analyze its physical properties and demonstrate ALMA's valuable contribution to solar physics.

## Contribution

It provides the first multi-wavelength analysis of a solar plasmoid using ALMA, revealing its possible temperature structures and highlighting ALMA's role in solar atmospheric studies.

## Key findings

- The plasmoid may be composed of 10^5 K plasma or a 10^4 K core with a hot envelope.
- ALMA data helps constrain the temperature and density of solar plasmoids.
- Future ALMA observations can achieve high spatial resolution comparable to other telescopes.

## Abstract

Eruptive phenomena such as plasmoid ejections or jets are an important feature of solar activity with the potential for improving our understanding of the dynamics of the solar atmosphere. Such ejections are often thought to be signatures of the outflows expected in regions of fast magnetic reconnection. The 304 A EUV line of Helium, formed at around 10^5 K, is found to be a reliable tracer of such phenomena, but the determination of physical parameters from such observations is not straightforward. We have observed a plasmoid ejection from an X-ray bright point simultaneously at millimeter wavelengths with ALMA, at EUV wavelengths with AIA, in soft X-rays with Hinode/XRT. This paper reports the physical parameters of the plasmoid obtained by combining the radio, EUV and X-ray data. As a result, we conclude that the plasmoid can consist either of (approximately) isothermal 10^5 K plasma that is optically thin at 100 GHz, or else a 10^4 K core with a hot envelope. The analysis demonstrates the value of the additional temperature and density constraints that ALMA provides, and future science observations with ALMA will be able to match the spatial resolution of space-borne and other high-resolution telescopes.