Search Publications
Relationships Among Magnetic Clouds, CMES, and Geomagnetic Storms
Gopalswamy, N.; Lepping, R. P.; Wu, C. C.
During solar cycle 23, 82 interplanetary magnetic clouds (MCs) were identified by the Magnetic Field Investigation (MFI) team using Wind (1995 - 2003) solar wind plasma and magnetic field data from solar minimum through the maximum of cycle 23. The average occurrence rate is 9.5 MCs per year for the overall period. It is found that some of the ano…
Seismic Emission from A M9.5-Class Solar Flare
Cally, P. S.; Lindsey, C.; Donea, A. -C. +2 more
Following the discovery of a few significant seismic sources at 6.0 mHz from the large solar flares of October 28 and 29, 2003, we have extended SOHO/MDI helioseismic observations to moderate M-class flares. We report the detection of seismic waves emitted from the β γ δ active region NOAA 9608 on September 9, 2001. A quite impulsive solar flare o…
Role of Sunspot and Sunspot-Group Rotation in Driving Sigmoidal Active Region Eruptions
Alexander, David; Tian, Lirong
We study active region NOAA 9684 (N06L285) which produced an X1.0/3B flare on November 4, 2001 associated with a fast CME (1810 km s−1) and the largest proton event (31 700 pfu) in cycle 23. SOHO/MDI continuum image data show that a large leading sunspot rotated counter-clockwise around its umbral center for at least 4 days prior to the…
Large-Scale Zonal Flows Near the Solar Surface
Thompson, M. J.; Howe, R.; Komm, R. +5 more
Migrating bands of weak, zonal flow, associated with the activity bands in the solar cycle, have been observed at the solar surface for some time. More recently, these flows have been probed deep within the convection zone using global helioseismology and examined in more detail close to the surface with the techniques of local helioseismology. We…
The May 13, 2005 Eruption: Observations, Data Analysis and Interpretation
Liu, C.; Yurchyshyn, V.; Abramenko, V. +1 more
In this study, we present detailed description and analysis of the May 13, 2005 eruption, the corresponding coronal mass ejection (CME) and intense geomagnetic storm observed near the Earth on May 15, 2005. This isolated two-ribbon M8.0 flare and the very fast CME occurred in a relatively simple magnetic configuration during a quiet period of sola…
Moving Magnetic Features in and out of Penumbral Filaments
Ravindra, B.
A time sequence of high-resolution SOHO/MDI magnetograms, Dopplergrams, and continuum images is used to study the moving magnetic features (MMFs) in and out of penumbral filaments. Precursors of MMFs have been observed inside the penumbral filaments. One hundred and fifteen out of 127 well-observed individual MMFs in the moat of two sunspots have …
A Quantitative Study on Magnetic Configuration for Active Regions
Guo, Juan; Zhang, Hongqi; Chumak, Oleg V. +1 more
As compared with the Mount Wilson Magnetic Classification (MWMC), effective distance (dE) is a useful parameter because it gives a quantitative measure of magnetic configuration in active regions. We have analyzed magnetograms of 24 active regions of different types with MWMC. We have studied the evolution of magnetic fields of five act…
Evolving Photospheric Flux Concentrations and Filament Dynamic Changes
Aulanier, G.; Schmieder, B.; Mein, P. +1 more
We analyze the role of weak photospheric flux concentrations that evolve in a filament channel, in the triggering of dynamic changes in the shape of a filament. The high polarimetric sensitivity of THEMIS allowed us to detect weak flux concentrations (few Gauss) associated with the filament development. The synoptic instruments (MDI, SOLIS) even i…
Shrinking and Cooling of Flare Loops in a Two-Ribbon Flare
Lin, Jun; Temmer, Manuela; Veronig, Astrid +2 more
We analyze the evolution of the flare/postflare-loop system in the two-ribbon flare of November 3, 2003, utilizing multi-wavelength observations that cover the temperature range from several tens of MK down to 104 K. A non-uniform growth of the loop system enables us to identify analogous patterns in the height-time, h(t), curves measur…
Automatic Detection and Classification of Coronal Mass Ejections
Jing, Ju; Wang, Haimin; Qu, Ming +1 more
We present an automatic algorithm to detect, characterize, and classify coronal mass ejections (CMEs) in Large Angle Spectrometric Coronagraph (LASCO) C2 and C3 images. The algorithm includes three steps: (1) production running difference images of LASCO C2 and C3; (2) characterization of properties of CMEs such as intensity, height, angular width…