Search Publications
Dependence of Geomagnetic Storms on Their Associated Halo CME Parameters
Moon, Y. -J.; Lee, Kyoung-Sun; Kim, R. -S. +1 more
We compare the geoeffective parameters of halo coronal mass ejections (CMEs). We consider 50 front-side full-halo CMEs (FFH CMEs), which are from the list of Michalek, Gopalswamy, and Yashiro (Solar Phys.246, 399, 2007), whose asymmetric-cone model parameters and earthward-direction parameter were available. For each CME we use its projected veloc…
Automated Detection, Characterization, and Tracking of Sunspots from SoHO/MDI Continuum Images
Mathew, Shibu K.; Goel, Suruchi
We describe a procedure for automated detection of sunspots from SoHO/MDI full-disk continuum images. The MDI Level-1.8 continuum images were first corrected for the limb darkening and stray light, and then were flat-fielded. Sunspots were extracted using a newly developed automated sunspot detection procedure, which is based on the level set, nam…
From Predicting Solar Activity to Forecasting Space Weather: Practical Examples of Research-to-Operations and Operations-to-Research
Biesecker, D. A.; Steenburgh, R. A.; Millward, G. H.
The successful transition of research to operations (R2O) and operations to research (O2R) requires, above all, interaction between the two communities. We explore the role that close interaction and ongoing communication played in the successful fielding of three separate developments: an observation platform, a numerical model, and a visualizati…
Sunspot Group Development in High Temporal Resolution
Ludmány, A.; Baranyi, T.; Muraközy, J.
The Solar and Heliospheric Observatory/Michelson Doppler Imager - Debrecen Data (SDD) sunspot catalogue provides an opportunity to study the details and development of sunspot groups on a large statistical sample. In particular, the SDD data allow the differential study of the leading and following parts with a temporal resolution of 1.5 hours. In…
The SUMER Data in the SOHO Archive
Bocchialini, K.; Wilhelm, K.; Curdt, W. +5 more
We have released an archive of all observational data of the VUV spectrometer Solar Ultraviolet Measurements of Emitted Radiation (SUMER) on SOHO that have been acquired until now. The operational phase started with `first light' observations on 27 January 1996 and will end in 2014. Future data will be added to the archive when they become availab…
Time Evolution of the Altitude of an Observed Coronal Wave
Parenti, S.; Schmieder, B.; Artzner, G. +1 more
The nature of coronal wave fronts is intensely debated. They are observed in several wavelength bands and are frequently interpreted as magnetosonic waves propagating in the lower solar atmosphere. However, they can also be attributed to the line-of-sight projection of the edges of coronal mass ejections. Therefore, estimating the altitude of thes…
Interaction Between Two CMEs During 14 - 15 February 2011 and Their Unusual Radio Signature
Shanmugaraju, A.; Prasanna Subramanian, S.; Ibrahim, M. Syed +1 more
We report a detailed analysis of an interaction between two coronal mass ejections (CMEs) that were observed on 14 - 15 February 2011 and the corresponding radio enhancement, which was similar to the "CME cannibalism" reported by Gopalswamy et al. (Astrophys. J.548, L91, 2001). A primary CME, with a mean field-of-view velocity of 669 km s−1
Automatic Tracking of Active Regions and Detection of Solar Flares in Solar EUV Images
Caballero, C.; Aranda, M. C.
Solar catalogs are frequently handmade by experts using a manual approach or semi-automated approach. The appearance of new tools is very useful because the work is automated. Nowadays it is impossible to produce solar catalogs using these methods, because of the emergence of new spacecraft that provide a huge amount of information. In this articl…
The Quest to Understand Supergranulation and Large-Scale Convection in the Sun
Hanasoge, Shravan M.; Sreenivasan, Katepalli R.
Surface granulation of the Sun is primarily a consequence of thermal transport in the outer 1 % of the radius. Its typical scale of about 1 - 2 Mm is set by the balance between convection, free-streaming radiation, and the strong density stratification in the surface layers. The physics of granulation is well understood, as demonstrated by the clo…
Hemispheric Distribution of Subsurface Kinetic Helicity and Its Variation with Magnetic Activity
Komm, R.; Pevtsov, A. A.; Gosain, S.
We study the hemispheric distribution of the kinetic helicity of subsurface flows in the near-surface layers of the solar convection zone and its variation with magnetic activity. We determine subsurface flows with a ring-diagram analysis applied to Global Oscillation Network Group (GONG) Dopplergrams and Dynamics Program data from the Michelson D…