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Responsibility of a Filament Eruption for the Initiation of a Flare, CME, and Blast Wave, and its Possible Transformation into a Bow Shock
Grechnev, V. V.; Chertok, I. M.; Kochanov, A. A. +3 more
Multi-instrument observations of two filament eruptions on 24 February and 11 May 2011 suggest the following updated scenario for eruptive flare, coronal mass ejection (CME), and shock wave evolution. An initial destabilization of a filament results in stretching out of the magnetic threads belonging to its body that are rooted in the photosphere …
Objective Image-Quality Assessment for High-Resolution Photospheric Images by Median Filter-Gradient Similarity
Cao, Wenda; Ji, Kaifan; Wang, Feng +6 more
All next-generation ground-based and space-based solar telescopes require a good quality-assessment metric to evaluate their imaging performance. In this paper, a new image quality metric, the median filter-gradient similarity (MFGS) is proposed for photospheric images. MFGS is a no-reference/blind objective image-quality metric (IQM) by a measure…
Low-Frequency Type-II Radio Detections and Coronagraph Data Employed to Describe and Forecast the Propagation of 71 CMEs/Shocks
St. Cyr, O. C.; Kaiser, M. L.; Gopalswamy, N. +3 more
Motivated by improving predictions of arrival times at Earth of shocks driven by coronal mass ejections (CMEs), we have analyzed 71 Earth-directed events in different stages of their propagation. The study is primarily based on approximated locations of interplanetary (IP) shocks derived from Type-II radio emissions detected by the Wind/WAVES expe…
3D Reconstruction of Interplanetary Scintillation (IPS) Remote-Sensing Data: Global Solar Wind Boundaries for Driving 3D-MHD Models
Odstrcil, D.; Davies, J. A.; Jackson, B. V. +6 more
The University of California, San Diego, time-dependent analyses of the heliosphere provide three-dimensional (3D) reconstructions of solar wind velocities and densities from observations of interplanetary scintillation (IPS). Using data from the Solar-Terrestrial Environment Laboratory, Japan, these reconstructions provide a real-time prediction …
Diagnostics of a Coronal Hole and the Adjacent Quiet Sun by The Hinode/EUV Imaging Spectrometer (EIS)
Srivastava, A. K.; Banerjee, D.; Kayshap, P.
A comparison between a coronal hole (CH) and the adjacent quiet Sun (QS) has been performed using the spectroscopic diagnostics of the Hinode/EUV Imaging Spectrometer (EIS). Based on spectral signatures, we identify the coronal funnels that play an important role in the formation and propagation of the nascent fast solar wind. From the observed li…
Spatially Resolved Energetic Electron Properties for the 21 May 2004 Flare from Radio Observations and 3D Simulations
Kontar, E. P.; Kuznetsov, A. A.
We investigated in detail the 21 May 2004 flare using simultaneous observations of the Nobeyama Radioheliograph, the Nobeyama Radiopolarimeters, the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), and the Solar and Heliospheric Observatory (SOHO). The flare images in different spectral ranges reveal a well-defined single flaring loo…
Limb Event Brightenings and Fast Ejection Using IRIS Mission Observations
Koutchmy, S.; Golub, L.; Tavabi, E.
The Interface Region Imaging Spectrograph (IRIS) of the recently commissioned NASA small explorer mission provides significantly more complete and higher resolution spectral coverage of the dynamical conditions inside the chromosphere and transition region (TR) than has been available ever before. High temporal, spatial (0.3″) and spect…
Null Point Distribution in Global Coronal Potential Field Extrapolations
Parnell, C. E.; Edwards, S. J.
Magnetic null points are points in space where the magnetic field is zero. Thus, they can be important sites for magnetic reconnection by virtue of the fact that they are weak points in the magnetic field and also because they are associated with topological structures, such as separators, which lie on the boundary between four topologically disti…
Evolution of Small-Scale Magnetic Elements in the Vicinity of Granular-Sized Swirl Convective Motions
Vargas Domínguez, S.; Balmaceda, L.; Domingo, V. +2 more
Advances in solar instrumentation have led to widespread use of time series to study the dynamics of solar features, especially at small spatial scales and at very fast cadences. Physical processes at such scales are important as building blocks for many other processes occurring from the lower to the upper layers of the solar atmosphere and beyon…
Observations of Near-Simultaneous Split-Band Solar Type-II Radio Bursts at Low Frequencies
Ramesh, R.; Kathiravan, C.; Hariharan, K.
We report ground-based radio spectral and polarimeter observations of two successive split-band Type-II bursts that occurred on 20 February 2014 at low frequencies (<100 MHz) in association with a solar coronal mass ejection (CME). The temporal interval between the onset of the two bursts was very small, ≈ one minute. Both of the bursts exhibit…