Search Publications
Comparative Analysis of a Transition Region Bright Point with a Blinker and Coronal Bright Point Using Multiple EIS Emission Lines
Orange, N. Brice; Oluseyi, Hakeem M.; Chesny, David L. +5 more
Since their discovery 20 year ago, transition region bright points have never been observed spectroscopically. Bright point properties have not been compared with similar transition region and coronal structures. In this work we have investigated three transient quiet Sun brightenings including a transition region bright point (TR BP), a coronal b…
Do Solar Coronal Holes Affect the Properties of Solar Energetic Particle Events?
Arge, C. N.; Gopalswamy, N.; Kahler, S. W. +1 more
The intensities and timescales of gradual solar energetic particle (SEP) events at 1 AU may depend not only on the characteristics of shocks driven by coronal mass ejections (CMEs), but also on large-scale coronal and interplanetary structures. It has long been suspected that the presence of coronal holes (CHs) near the CMEs or near the 1-AU magne…
On Thermal-Pulse-Driven Plasma Flows in Coronal Funnels as Observed by the Hinode/ EUV Imaging Spectrometer (EIS)
Srivastava, A. K.; Konkol, P.; Murawski, K. +2 more
Using one-arcsecond-slit-scan observations from the Hinode/EUVImagingSpectrometer (EIS) on 5 February 2007, we find the plasma outflows in the open and expanding coronal funnels at the eastern boundary of AR 10940. The Doppler-velocity map of Fe XII 195.120 Å shows the diffuse closed-loop system to be mostly red-shifted. The open arches (funnels) …
A Full-Sun Magnetic Index from Helioseismology Inferences
Hill, F.; Pérez Hernández, F.; Braun, D. C. +4 more
Solar magnetic indices are used to model the solar irradiance and ultimately to forecast it. However, the observation of such indices is generally limited to the Earth-facing hemisphere of the Sun. Seismic maps of the far side of the Sun have proven their capability to locate and track medium-large active regions at the non-visible hemisphere. We …
The Role of Magnetic Fields in Transient Seismic Emission Driven by Atmospheric Heating in Flares
Lindsey, C.; Hudson, H. S.; Donea, A. -C. +1 more
Transient seismic emission in flares remains largely mysterious. Its discoverers proposed that seismic transients are driven by impulsive heating of the flaring chromosphere. Simulations of such heating show strong shocks, but these are damped by heavy radiative losses as they proceed downward. Because compression of the gas the shock enters both …
Automated Processing of LASCO Coronal Images: Spurious Point-Source-Filtering and Missing-Blocks Correction
Llebaria, A.; Lamy, P.; Boclet, B. +1 more
We report on automated procedures for correcting the images of the LASCO coronagraph for i) spurious quasi-point-sources such as the impacts of cosmic rays, stars, and planets, and ii) the absence of signal due to transmission errors or dropouts, which results in blocks of missing information in the images. Correcting for these undesirable artifac…
Properties of Magnetic Neutral Line Gradients and Formation of Filaments
Karachik, Nina V.; Pevtsov, Alexei A.
We investigate the gradients of magnetic fields across neutral lines (NLs) and compare their properties for NLs with and without chromospheric filaments. Our results show that there is a range of preferred magnetic field gradients where the filament formation is enhanced. On the other hand, a horizontal gradient of the magnetic field across an NL …
An Ensemble Study of a January 2010 Coronal Mass Ejection (CME): Connecting a Non-obvious Solar Source with Its ICME/Magnetic Cloud
Webb, D. F.; Möstl, C.; Farrugia, C. J. +9 more
A distinct magnetic cloud (MC) was observed in-situ at the Solar TErrestrial RElations Observatory (STEREO)-B on 20 - 21 January 2010. About three days earlier, on 17 January, a bright flare and coronal mass ejection (CME) were clearly observed by STEREO-B, which suggests that this was the progenitor of the MC. However, the in-situ speed of the ev…
Two-Way Frequency Fluctuations Observed During Coronal Radio Sounding Experiments
Pätzold, M.; Bird, M. K.; Efimov, A. I. +5 more
Coronal radio-sounding experiments were carried out using two-way coherent dual-frequency carrier signals of the ESA spacecraft Rosetta (ROS) in 2006. Frequency measurements recorded at both NASA and ESA tracking stations (sample rate: 1 Hz) are analyzed in this work. Spectral analysis of the S-band, X-band, and differential frequency records has …
The Interaction Between Coronal Mass Ejections and Streamers: A Statistical View over 15 Years (1996 - 2010)
Llebaria, A.; Lamy, P.; Floyd, O.
We report on the statistical analysis of the interaction between coronal mass ejections (CMEs) and streamers based on 15 years (from 1996 to 2010 inclusive) of observation of the solar corona with the LASCO-C2 coronagraph. We used synoptic maps and improved the method of analysis of past investigations by implementing an automatic detection of bot…