SIMULTANEOUS IRIS AND HINODE/EIS OBSERVATIONS AND MODELING OF THE 2014 OCTOBER 27 X2.0 CLASS FLARE

Journal Article · Sun Jan 10 00:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/816/2/89· OSTI ID:22521699

Polito, V.; Reep, J. W.; Del Zanna, G.; Mason, H. E. ^[1]; Reeves, K. K.; Golub, L. ^[2]; Simões, P. J. A. ^[3]; Dudík, J. ^[4]

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1. DAMTP, CMS, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)
2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 01238 (United States)
3. SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)
4. Astronomical Institute, Academy of Sciences of the Czech Republic, 25165 Ondrejov (Czech Republic)

We present a study of the X2-class flare which occurred on 2014 October 27 and was observed with the Interface Region Imaging Spectrograph (IRIS) and the EUV Imaging Spectrometer (EIS) on board the Hinode satellite. Thanks to the high cadence and spatial resolution of the IRIS and EIS instruments, we are able to compare simultaneous observations of the Fe xxi 1354.08 Å and Fe xxiii 263.77 Å high-temperature emission (≳10 MK) in the flare ribbon during the chromospheric evaporation phase. We find that IRIS observes completely blueshifted Fe xxi line profiles, up to 200 km s{sup −1} during the rise phase of the flare, indicating that the site of the plasma upflows is resolved by IRIS. In contrast, the Fe xxiii line is often asymmetric, which we interpret as being due to the lower spatial resolution of EIS. Temperature estimates from SDO/AIA and Hinode/XRT show that hot emission (log(T[K]) > 7.2) is first concentrated at the footpoints before filling the loops. Density-sensitive lines from IRIS and EIS give estimates of electron number density of ≳10{sup 12} cm{sup −3} in the transition region lines and 10{sup 10} cm{sup −3} in the coronal lines during the impulsive phase. In order to compare the observational results against theoretical predictions, we have run a simulation of a flare loop undergoing heating using the HYDRAD 1D hydro code. We find that the simulated plasma parameters are close to the observed values that are obtained with IRIS, Hinode, and AIA. These results support an electron beam heating model rather than a purely thermal conduction model as the driving mechanism for this flare.

• OSTI ID: 22521699
• Journal Information: Astrophysical Journal, Vol. 816, 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
CHROMOSPHERE
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
DENSITY
ELECTRON BEAMS
EVAPORATION
H CODES
HEATING
PLASMA
SATELLITES
SOLAR ELECTRONS
SOLAR FLARES
SPATIAL RESOLUTION
SUN
THERMAL CONDUCTION