Search Publications
Relation Between Type II Bursts and CMEs Inferred from STEREO Observations
Kaiser, M. L.; Howard, R. A.; Gopalswamy, N. +6 more
The inner coronagraph (COR1) of the Solar Terrestrial Relations Observatory (STEREO) mission has made it possible to observe CMEs in the spatial domain overlapping with that of the metric type II radio bursts. The type II bursts were associated with generally weak flares (mostly B and C class soft X-ray flares), but the CMEs were quite energetic. …
Automated Coronal Hole Detection Using Local Intensity Thresholding Techniques
Gallagher, Peter T.; Krista, Larisza D.
We identify coronal holes using a histogram-based intensity thresholding technique and compare their properties to fast solar wind streams at three different points in the heliosphere. The thresholding technique was tested on EUV and X-ray images obtained using instruments onboard STEREO, SOHO and Hinode. The full-disk images were transformed into…
Statistical Assessment of Photospheric Magnetic Features in Imminent Solar Flare Predictions
Jing, Ju; Wang, Haimin; Yurchyshyn, Vasyl +3 more
In this study we use the ordinal logistic regression method to establish a prediction model, which estimates the probability for each solar active region to produce X-, M-, or C-class flares during the next 1-day time period. The three predictive parameters are (1) the total unsigned magnetic flux Tflux, which is a measure of an active …
Multispacecraft Observations of Magnetic Clouds and Their Solar Origins between 19 and 23 May 2007
Liu, Y.; Luhmann, J. G.; Russell, C. T. +11 more
We analyze a series of complex interplanetary events and their solar origins that occurred between 19 and 23 May 2007 using observations by the STEREO and Wind satellites. The analyses demonstrate the new opportunities offered by the STEREO multispacecraft configuration for diagnosing the structure of in situ events and relating them to their sola…
Short-Term Solar Flare Prediction Using a Sequential Supervised Learning Method
Huang, Xin; Yu, Daren; Wang, Huaning +1 more
Solar flares are powered by the energy stored in magnetic fields, so evolutionary information of the magnetic field is important for short-term prediction of solar flares. However, the existing solar flare prediction models only use the current information of the active region. A sequential supervised learning method is introduced to add the evolu…
Automated detection of EUV Polar Coronal Holes during Solar Cycle 23
Hess Webber, S. A.; Pesnell, W. D.; Young, C. A. +1 more
A new method for automated detection of polar coronal holes is presented. This method, called perimeter tracing, uses a series of 171, 195, and 304 Å full disk images from the Extreme ultraviolet Imaging Telescope (EIT) on SOHO over solar cycle 23 to measure the perimeter of polar coronal holes as they appear on the limbs. Perimeter tracing minimi…
CME Projection Effects Studied with STEREO/COR and SOHO/LASCO
Temmer, M.; Veronig, A. M.; Preiss, S.
Based on a set of 11 CME events we study the impact of projection effects by tracking CME leading edge features in the plane of sky (traditional CME tracking) from combined STEREO-SECCHI and SOHO-LASCO observations up to 20R⊙. By using CME observations from two vantage points and applying triangulation techniques, the source region loca…
Evidence of Magnetic Helicity in Emerging Flux and Associated Flare
Aulanier, G.; Schmieder, B.; Malherbe, J. M. +1 more
The aim of this paper is to look at the magnetic helicity structure of an emerging active region and show that both emergence and flaring signatures are consistent with a same sign for magnetic helicity. We present a multiwavelength analysis of an M1.6 flare occurring in the NOAA active region 10365 on 27 May 2003, in which a large new bipole emer…
Small Solar Wind Transients and Their Connection to the Large-Scale Coronal Structure
Luhmann, J. G.; Russell, C. T.; Kilpua, E. K. J. +9 more
It has been realized for some time that the slow solar wind with its embedded heliospheric current sheet often exhibits complex features suggesting at least partially transient origin. In this paper we investigate the structure of the slow solar wind using the observations by the Wind and STEREO spacecraft during two Carrington rotations (2054 and…
The ARTEMIS Catalog of LASCO Coronal Mass Ejections. Automatic Recognition of Transient Events and Marseille Inventory from Synoptic maps
Llebaria, A.; Lamy, P.; Boursier, Y. +2 more
The LASCO-C2 coronagraph aboard the SOHO solar observatory has been providing a continuous flow of coronal images since 1996. Synoptic maps for each Carrington rotation have been built from these images, and offer a global view of the temporal evolution of the solar corona, particularly the occurrence of transient events. Coronal Mass Ejections (C…