Search Publications
A Helicity-Based Method to Infer the CME Magnetic Field Magnitude in Sun and Geospace: Generalization and Extension to Sun-Like and M-Dwarf Stars and Implications for Exoplanet Habitability
Patsourakos, S.; Georgoulis, M. K.
Patsourakos et al. (Astrophys. J.817, 14, 2016) and Patsourakos and Georgoulis (Astron. Astrophys.595, A121, 2016) introduced a method to infer the axial magnetic field in flux-rope coronal mass ejections (CMEs) in the solar corona and farther away in the interplanetary medium. The method, based on the conservation principle of magnetic helicity, …
Solar Energetic Particle Forecasting Algorithms and Associated False Alarms
Dalla, S.; Walsh, R. W.; Swalwell, B.
Solar energetic particle (SEP) events are known to occur following solar flares and coronal mass ejections (CMEs). However, some high-energy solar events do not result in SEPs being detected at Earth, and it is these types of event which may be termed "false alarms".
Automated Spatiotemporal Analysis of Fibrils and Coronal Rain Using the Rolling Hough Transform
Schad, Thomas
A technique is presented that automates the direction characterization of curvilinear features in multidimensional solar imaging datasets. It is an extension of the Rolling Hough Transform (RHT) technique presented by Clark, Peek, and Putman (Astrophys. J.789, 82, 2014), and it excels at rapid quantification of spatial and spatiotemporal feature o…
Comparative Study of the Three-Dimensional Thermodynamical Structure of the Inner Corona of Solar Minimum Carrington Rotations 1915 and 2081
Frazin, Richard A.; Vásquez, Alberto M.; Nuevo, Federico A. +1 more
Using differential emission measure tomography (DEMT) based on time series of EUV images, we carry out a quantitative comparative analysis of the three-dimensional (3D) structure of the electron density and temperature of the inner corona (r <1.25 R⊙) between two specific rotations selected from the last two solar minima, namely Carr…
Characterizing Solar Energetic Particle Event Profiles with Two-Parameter Fits
Kahler, Stephen W.; Ling, Alan G.
The intensity-time profiles of solar energetic (E >10 MeV) particle (SEP) events observed at 1 AU reflect a number of physical processes involving solar injection and interplanetary transport. In addition to energy spectral and composition studies, SEP intensity-time profiles are the basis for diagnostic timescales needed for describing and mod…
Interplanetary Magnetic Flux Ropes as Agents Connecting Solar Eruptions and Geomagnetic Activities
Marubashi, K.; Cho, K. -S.; Ishibashi, H.
We investigate the solar wind structure for 11 cases that were selected for the campaign study promoted by the International Study of Earth-affecting Solar Transients (ISEST) MiniMax24 Working Group 4. We can identify clear flux rope signatures in nine cases. The geometries of the nine interplanetary magnetic flux ropes (IFRs) are examined with a …
The 26 December 2001 Solar Eruptive Event Responsible for GLE63: III. CME, Shock Waves, and Energetic Particles
Klein, K. -L.; Grechnev, V. V.; Kochanov, A. A. +2 more
The SOL2001-12-26 moderate solar eruptive event (GOES importance M7.1, microwaves up to 4000 sfu at 9.4 GHz, coronal mass ejection (CME) speed 1446 km s−1) produced strong fluxes of solar energetic particles and ground-level enhancement (GLE) of cosmic-ray intensity (GLE63). To find a possible reason for the atypically high proton outco…
Review of Image Quality Measures for Solar Imaging
Popowicz, Adam; Bernacki, Krzysztof; Orlov, Valeri +1 more
Observations of the solar photosphere from the ground encounter significant problems caused by Earth's turbulent atmosphere. Before image reconstruction techniques can be applied, the frames obtained in the most favorable atmospheric conditions (the so-called lucky frames) have to be carefully selected. However, estimating the quality of images co…
Apparent and Intrinsic Evolution of Active Region Upflows
Janvier, Miho; Baker, Deborah; Démoulin, Pascal +1 more
We analyze the evolution of Fe XII coronal plasma upflows from the edges of ten active regions (ARs) as they cross the solar disk using the Hinode Extreme Ultraviolet Imaging Spectrometer (EIS) to do this. Confirming the results of Démoulin et al. (Sol. Phys.283, 341, 2013), we find that for each AR there is an observed long-term evolution of the …
The 26 December 2001 Solar Eruptive Event Responsible for GLE63. II. Multi-Loop Structure of Microwave Sources in a Major Long-Duration Flare
Kochanov, A. A.; Kiselev, V. I.; Uralov, A. M. +1 more
Our analysis of the observations of the SOL2001-12-26 event, which was related to ground-level enhancement of cosmic-ray intensity GLE63, including microwave spectra and images from the Nobeyama Radioheliograph at 17 and 34 GHz, from the Siberian Solar Radio Telescope at 5.7 GHz, and from the Transition Region and Coronal Explorer in 1600 Å, has l…