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Ellerman Bombs at High Resolution. III. Simultaneous Observations with IRIS and SST
De Pontieu, B.; Carlsson, M.; Rouppe van der Voort, L. H. M. +2 more
Ellerman bombs (EBs) are transient brightenings of the extended wings of the solar Balmer lines in emerging active regions. We describe their properties in the ultraviolet lines sampled by the Interface Region Imaging Spectrograph (IRIS), using simultaneous imaging spectroscopy in Hα with the Swedish 1-m Solar Telescope (SST) and ultraviolet image…
Temporal Evolution of Multiple Evaporating Ribbon Sources in a Solar Flare
Cauzzi, G.; Graham, D. R.
We present new results from the Interface Region Imaging Spectrograph (IRIS) showing the dynamic evolution of chromospheric evaporation and condensation in a flare ribbon, with the highest temporal and spatial resolution to date. IRIS observed the entire impulsive phase of the X-class flare SOL2014-09-10T17:45 using a 9.4 s cadence “sit-and-stare”…
Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. II. Numerical Aspects
De Pontieu, B.; Yokoyama, T.; Okamoto, T. J. +3 more
Transverse magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere and may be responsible for generating the Sun’s million-degree outer atmosphere. However, direct evidence of the dissipation process and heating from these waves remains elusive. Through advanced numerical simulations combined with appropriate forward modeling of a p…
Temporal Evolution of Chromospheric Evaporation: Case Studies of the M1.1 Flare on 2014 September 6 and X1.6 Flare on 2014 September 10
Reeves, Katharine K.; Chen, Bin; Liu, Wei +3 more
With observations from the Interface Region Imaging Spectrograph, we track the complete evolution of ∼11 MK evaporation flows in an M1.1 flare on 2014 September 6 and an X1.6 flare on 2014 September 10. These hot flows, as indicated by the blueshifted Fe xxi 1354.08 Å line, evolve smoothly with a velocity decreasing exponentially from ∼200 km s
The Multithermal and Multi-stranded Nature of Coronal Rain
Rouppe van der Voort, L.; Pereira, T. M. D.; Scullion, E. +2 more
We analyze coordinated observations of coronal rain in loops, spanning chromospheric, transition region (TR), and coronal temperatures with sub-arcsecond spatial resolution. Coronal rain is found to be a highly multithermal phenomenon with a high degree of co-spatiality in the multi-wavelength emission. EUV darkening and quasi-periodic intensity v…
Homologous Helical Jets: Observations By IRIS, SDO, and Hinode and Magnetic Modeling With Data-Driven Simulations
Golub, L.; Tian, H.; Cheung, Mark C. M. +18 more
We report on observations of recurrent jets by instruments on board the Interface Region Imaging Spectrograph, Solar Dynamics Observatory (SDO), and Hinode spacecraft. Over a 4 hr period on 2013 July 21, recurrent coronal jets were observed to emanate from NOAA Active Region 11793. Far-ultraviolet spectra probing plasma at transition region temper…
Quasi-periodic Slipping Magnetic Reconnection During an X-class Solar Flare Observed by the Solar Dynamics Observatory and Interface Region Imaging Spectrograph
Li, Ting; Zhang, Jun
We first report the quasi-periodic slipping motion of flare loops during an eruptive X-class flare on 2014 September 10. The slipping motion was investigated at a specific location along one of the two ribbons and can be observed throughout the impulsive phase of the flare. The apparent slipping velocity was 20-110 km s-1, and the assoc…
Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. I. Observational Aspects
Van Doorsselaere, Tom; Antolin, Patrick; De Pontieu, Bart +3 more
Transverse magnetohydrodynamic waves have been shown to be ubiquitous in the solar atmosphere and can, in principle, carry sufficient energy to generate and maintain the Sun’s million-degree outer atmosphere or corona. However, direct evidence of the dissipation process of these waves and subsequent heating has not yet been directly observed. Here…
The 2014 March 29 X-flare: Subarcsecond Resolution Observations of Fe XXI λ1354.1
Jaeggli, Sarah; Tian, Hui; Young, Peter R.
The Interface Region Imaging Spectrometer (IRIS) is the first solar instrument to observe ~10 MK plasma at subarcsecond spatial resolution through imaging spectroscopy of the Fe XXI λ1354.1 forbidden line. IRIS observations of the X1 class flare that occurred on 2014 March 29 at 17:48 UT reveal Fe XXI emission from both the flare ribbons and the p…
The Formation of IRIS Diagnostics. IV. The Mg II Triplet Lines as a New Diagnostic for Lower Chromospheric Heating
De Pontieu, Bart; Hansteen, Viggo; Carlsson, Mats +1 more
A triplet of subordinate lines of Mg ii exists in the region around the h&k lines. In solar spectra these lines are seen mostly in absorption, but in some cases can become emission lines. The aim of this work is to study the formation of this triplet, and investigate any diagnostic value they can bring. Using 3D radiative magnetohydrodynamic s…