Search Publications
Correlation Analyses Between the Characteristic Times of Gradual Solar Energetic Particle Events and the Properties of Associated Coronal Mass Ejections
Wang, Yuming; Wang, C. B.; Pan, Z. H. +1 more
It is generally believed that gradual solar energetic particles (SEPs) are accelerated by shocks associated with coronal mass ejections (CMEs). Using an ice-cream cone model, the radial speed and angular width of 95 CMEs associated with SEP events during 1998 - 2002 are calculated from SOHO/LASCO observations. Then, we investigate the relationship…
Comparisons of Supergranule Characteristics During the Solar Minima of Cycles 22/23 and 23/24
Williams, Peter E.; Pesnell, W. Dean
Supergranulation is a component of solar convection that manifests itself on the photosphere as a cellular network of around 35 Mm across, with a turnover lifetime of 1 - 2 days. It is strongly linked to the structure of the magnetic field. The horizontal, divergent flows within supergranule cells carry local field lines to the cell boundaries, wh…
Validation of CME Detection Software (CACTus) by Means of Simulated Data, and Analysis of Projection Effects on CME Velocity Measurements
Berghmans, D.; Poedts, S.; Robbrecht, E. +3 more
In the context of space weather forecasting, an automated detection of coronal mass ejections (CMEs) becomes more and more important for efficiently handling a large data flow which is expected from recently-launched and future solar missions. In this paper we validate the detection software package "CACTus" by applying the program to synthetic da…
Energy Release During Slow Long-Duration Flares Observed by RHESSI
Kołomański, S.; Mrozek, T.; Bąk-Stęślicka, U.
Slow long-duration events (SLDEs) are flares characterized by the long duration of their rising phase. In many such cases the impulsive phase is weak without typical short-lasting pulses. Instead, smooth, long-lasting hard X-ray (HXR) emission is observed. We analyzed hard X-ray emission and morphology of six selected SLDEs. In our analysis we uti…
The 17 January 2005 Complex Solar Radio Event Associated with Interacting Fast Coronal Mass Ejections
Klein, K. -L.; Hillaris, A.; Malandraki, O. +6 more
On 17 January 2005 two fast coronal mass ejections were recorded in close succession during two distinct episodes of a 3B/X3.8 flare. Both were accompanied by metre-to-kilometre type-III groups tracing energetic electrons that escape into the interplanetary space and by decametre-to-hectometre type-II bursts attributed to CME-driven shock waves. A…
Acoustic Power Absorption and its Relation to Vector Magnetic Field of a Sunspot
Venkatakrishnan, P.; Gosain, S.; Mathew, S. K.
The distribution of acoustic power over sunspots shows an enhanced absorption near the umbra - penumbra boundary. Previous studies revealed that the region of enhanced absorption coincides with the region of strongest transverse potential field. The aim of this paper is to i) utilize the high-resolution vector magnetograms derived using Hinode SOT…
Observational Signatures of Impulsively Heated Coronal Loops: Power-Law Distribution of Energies
Erdélyi, R.; Bradshaw, S. J.; Taroyan, Y.
It has been established that small scale heating events, known as nanoflares, are important for solar coronal heating if the power-law distribution of their energies has a slope α steeper than −2 (α<−2). Forward modeling of impulsively heated coronal loops with a set of prescribed power-law indices α is performed. The power-law distribution is …
Correlation between CME and Flare Parameters (with and without Type II Bursts)
Moon, Y. -J.; Shanmugaraju, A.; Vršnak, Bojan
CMEs and flares are the two energetic phenomena on the Sun responsible for generating shocks. Our main aim is to study the relation between the physical properties of CMEs and flares associated with and without type II radio bursts. We considered a set of 290 SOHO/LASCO CMEs associated with GOES X-ray flares observed during the period from January…
Combined Analysis of Ultraviolet and Radio Observations of the 7 May 2004 CME/Shock Event
Mancuso, Salvatore
We report results from the combined analysis of UV and radio observations of a CME-driven shock observed on 7 May 2004 above the southeast limb of the Sun at 1.86 R⊙ with the Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory (SOHO). The coronal mass ejection (CME) was first detected in white-lig…
Observables Indicating Two Major Coronal Mass Ejections During the WHI
Nitta, N. V.
Two of the five fast (v≳900 km s−1) coronal mass ejections (CMEs) between January 2007 and December 2009 were observed during the Whole Heliosphere Interval (WHI: 20 March - 16 April 2008). The main purpose of this article is to discuss possible observational signatures that could have been used to predict these CMEs. During the WHI, th…