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Title: The First ALMA Observation of a Solar Plasmoid Ejection from an X-Ray Bright Point

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 10{sup 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 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 ∼10{sup 5} K plasma that is optically thin at 100 GHz, or a ∼10{sup 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.

Authors:
 [1];  [2];  [3];  [4];  [5]
  1. National Astronomical Observatory of Japan, Tokyo, 181-8588 (Japan)
  2. School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom)
  3. Space Vehicles Directorate, Air Force Research Laboratory, Kirtland AFB, NM 87117-5776 (United States)
  4. National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)
  5. Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, 464-8601 (Japan)
Publication Date:
OSTI Identifier:
22654478
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 841; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; DENSITY; EXTREME ULTRAVIOLET SPECTRA; GAMMA RADIATION; GHZ RANGE; HELIUM; LIMITING VALUES; MAGNETIC RECONNECTION; PLASMA; PLASMOIDS; SOFT X RADIATION; SOLAR ACTIVITY; SOLAR ATMOSPHERE; SPACE; SPATIAL RESOLUTION; SUN; TELESCOPES; ULTRAVIOLET RADIATION; WAVELENGTHS

Citation Formats

Shimojo, Masumi, Hudson, Hugh S., White, Stephen M., Bastian, Timothy S., and Iwai, Kazumasa, E-mail: masumi.shimojo@nao.ac.jp. The First ALMA Observation of a Solar Plasmoid Ejection from an X-Ray Bright Point. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA70E3.
Shimojo, Masumi, Hudson, Hugh S., White, Stephen M., Bastian, Timothy S., & Iwai, Kazumasa, E-mail: masumi.shimojo@nao.ac.jp. The First ALMA Observation of a Solar Plasmoid Ejection from an X-Ray Bright Point. United States. doi:10.3847/2041-8213/AA70E3.
Shimojo, Masumi, Hudson, Hugh S., White, Stephen M., Bastian, Timothy S., and Iwai, Kazumasa, E-mail: masumi.shimojo@nao.ac.jp. Sat . "The First ALMA Observation of a Solar Plasmoid Ejection from an X-Ray Bright Point". United States. doi:10.3847/2041-8213/AA70E3.
@article{osti_22654478,
title = {The First ALMA Observation of a Solar Plasmoid Ejection from an X-Ray Bright Point},
author = {Shimojo, Masumi and Hudson, Hugh S. and White, Stephen M. and Bastian, Timothy S. and Iwai, Kazumasa, E-mail: masumi.shimojo@nao.ac.jp},
abstractNote = {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 10{sup 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 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 ∼10{sup 5} K plasma that is optically thin at 100 GHz, or a ∼10{sup 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.},
doi = {10.3847/2041-8213/AA70E3},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 841,
place = {United States},
year = {Sat May 20 00:00:00 EDT 2017},
month = {Sat May 20 00:00:00 EDT 2017}
}