PROPERTIES OF CHROMOSPHERIC EVAPORATION AND PLASMA DYNAMICS OF A SOLAR FLARE FROM IRIS OBSERVATIONS

Journal Article · Mon Jun 01 00:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/805/2/167· OSTI ID:22522362

Sadykov, Viacheslav M.; Dominguez, Santiago Vargas; Kosovichev, Alexander G. ^[1]; Sharykin, Ivan N.; Struminsky, Alexei B.; Zimovets, Ivan ^[2]

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1. Big Bear Solar Observatory, New Jersey Institute of Technology, Big Bear City, CA 92314 (United States)
2. Space Research Institute (IKI) of Russian Academy of Sciences, Moscow 117997 (Russian Federation)

The dynamics of hot chromospheric plasma of solar flares is a key to understanding the mechanisms of flare energy release and particle acceleration. A moderate M1.0 class flare of 2014 June 12, (SOL2014-06-12T21:12) was simultaneously observed by NASA's Interface Region Imaging Spectrograph (IRIS) and other spacecraft, and also by the New Solar Telescope at the BBSO. This paper presents the first part of our investigation focused on analysis of the IRIS data. Our analysis of the IRIS data in different spectral lines reveals a strong redshifted jet-like flow with a speed of ∼100 km s{sup −1} of the chromospheric material before the flare. Strong nonthermal emission of the C ii k 1334.5 Å line, formed in the chromosphere–corona transition region, is observed at the beginning of the impulsive phase in several small (with a size of ∼1″) points. It is also found that the C ii k line is redshifted across the flaring region before, during, and after the impulsive phase. A peak of integrated emission of the hot (1.1 · 10{sup 7} K) plasma in the Fe xxi 1354.1 Å line is detected approximately five minutes after the integrated emission peak of the lower temperature C ii k. A strong blueshift of the Fe xxi line across the flaring region corresponds to evaporation flows of the hot chromospheric plasma with a speed of 50 km s{sup −1}. Additional analysis of the RHESSI data supports the idea that the upper chromospheric dynamics observed by IRIS has features of “gentle” evaporation driven by heating of the solar chromosphere by accelerated electrons and by a heat flux from the flare energy release site.

• OSTI ID: 22522362
• Journal Information: Astrophysical Journal, Vol. 805, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCELERATION
CHROMOSPHERE
ELECTRONS
EMISSION
EVAPORATION
FLARING
HEAT FLUX
HEATING
JETS
MAGNETIC FIELDS
PLASMA
RED SHIFT
SOLAR FLARES
SPACE VEHICLES
SUN
TELESCOPES
ULTRAVIOLET RADIATION
VELOCITY