The first ALMA observation of a solar plasmoid ejection from an X-ray bright point

Shimojo, M., Hudson, H. S. , White, S. M., Bastian, T. S. and Iwai, K. (2017) The first ALMA observation of a solar plasmoid ejection from an X-ray bright point. Astrophysical Journal Letters, 841(1), L5. (doi: 10.3847/2041-8213/aa70e3)

Abstract

Eruptive phenomena such as plasmoid ejections or jets are important features of solar activity and have the potential to improve 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 Å EUV line of helium, formed at around 105 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 SDO/AIA, and 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 ~105 K plasma that is optically thin at 100 GHz, or a ~104 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.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hudson, Dr Hugh
• Authors: Shimojo, M., Hudson, H. S., White, S. M., Bastian, T. S., and Iwai, K.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Astrophysical Journal Letters
• Publisher: IOP Publishing
• ISSN: 2041-8205
• ISSN (Online): 2041-8213
• Published Online: 17 May 2017
• Copyright Holders: Copyright © 2017 The American Astronomical Societ
• First Published: First published in Astrophysical Journal Letters 841(1):L5
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher