Search Publications
Extreme Ultra-Violet Spectroscopy of the Lower Solar Atmosphere During Solar Flares (Invited Review)
Milligan, Ryan O.
The extreme ultra-violet (EUV) portion of the solar spectrum contains a wealth of diagnostic tools for probing the lower solar atmosphere in response to an injection of energy, particularly during the impulsive phase of solar flares. These include temperature- and density-sensitive line ratios, Doppler-shifted emission lines, nonthermal broadening…
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…
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…
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…
Calibration of Hinode/XRT for Coalignment
McKenzie, David E.; Yoshimura, Keiji
We present coalignment calibration procedures for the X-ray Telescope (XRT) onboard the Hinode satellite. We performed not only an XRT stand-alone calibration, but also cross calibration using data from the Helioseismic and Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). Several new me…
Identifying and Tracking of Peripheral and Central Umbral Dots
Yang, Yunfei; Ji, Kaifan; Feng, Song +3 more
Umbral dots (UDs) are small isolated brightening observed in sunspot umbrae. They are usually classified into peripheral UDs (PUDs) and central UDs (CUDs) according to their positions inside an umbra. To accurately investigate the similarities and the distinctions between PUDs and CUDs and better understand their formation mechanisms, we propose a…
Families of Granules, Flows, and Acoustic Events in the Solar Atmosphere from Hinode Observations
Roudier, T.; Rieutord, M.; Malherbe, J. -M. +1 more
We investigate the relationship between trees of fragmenting granules (TFG), horizontal and vertical flows, and acoustic events (AE) in the photospheric network. AE are spatially concentrated and short-duration locations of acoustic energy flux. We performed observations at disk center of a 2D field of view (FOV) with high spatial and temporal res…
Atmospheric Response of an Active Region to New Small Flux Emergence
Harra, L.; Green, L.; Shelton, D.
We investigate the atmospheric response to a small emerging flux region (EFR) that occurred in the positive polarity of Active Region 11236 on 23 - 24 June 2011. Data from the Solar Dynamics Observatory's Atmospheric Imaging Assembly (AIA), the Helioseismic and Magnetic Imager (HMI), and Hinode's EUV imaging spectrometer (EIS) are used to determin…
Reduced Coronal Emission Above Large Isolated Sunspots
Gary, D. E.; Shibasaki, K.; Peterova, N. G. +2 more
We analysed specific regions of reduced soft X-ray and microwave emission in five large isolated sunspots. The Nobeyama Radioheliograph 17 GHz observations reveal a local depression of microwave brightness in the peripheral area of the sunspots. The depression regions appear light (weak absorption) in the He 10830 Å line in areas with extended (op…
The Relationship Between Solar Coronal X-Ray Brightness and Active Region Magnetic Fields: A Study Using High-Resolution Hinode Observations
Hazra, Soumitra; Nandy, Dibyendu; Ravindra, B.
By using high-resolution observations of nearly co-temporal and co-spatial Solar Optical Telescope spectropolarimeter and X-Ray Telescope coronal X-ray data onboard Hinode, we revisit the problematic relationship between global magnetic quantities and coronal X-ray brightness. Co-aligned vector magnetogram and X-ray data were used for this study. …