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

Journal Article · Sat May 20 00:00:00 EDT 2017 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8213/AA70E3· OSTI ID:22654478

Shimojo, Masumi ^[1]; Hudson, Hugh S. ^[2]; White, Stephen M. ^[3]; Bastian, Timothy S. ^[4]; Iwai, Kazumasa ^[5]

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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)

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.

• OSTI ID: 22654478
• Journal Information: Astrophysical Journal Letters, Vol. 841, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

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