Search Publications
Spatial and Temporal Noise in Solar EUV Observations
Delouille, V.; Hochedez, J. -F.; Chainais, P.
Solar telescopes will never be able to resolve the smallest events at their intrinsic physical scales. Pixel signals recorded by SOHO/(CDS, EIT, SUMER), STEREO/SECCHI/ EUVI, TRACE, SDO/AIA, and even by the future Solar Orbiter EUI/HRI contain an inherent "spatial noise" since they represent an average of the solar signal present at subpixel scales…
Enhanced p-Mode Absorption Seen Near the Sunspot Umbral Penumbral Boundary
Mathew, Shibu K.
We investigate p-mode absorption in a sunspot using SOHO/MDI high-resolution Doppler images. The Doppler power computed from a 3.5-hour data set is used for studying the absorption in a sunspot. The result shows an enhancement in absorption near the umbral - penumbral boundary of the sunspot. We attempt to relate the observed absorption with the m…
Gnevyshev Peaks and Gaps for Coronal Mass Ejections of Different Widths Originating in Different Solar Position Angles
Kane, R. P.
The sunspot number series at the peak of sunspot activity often has two or three peaks (Gnevyshev peaks; Gnevyshev, Solar Phys.1, 107, 1967; Solar Phys.51, 175, 1977). The sunspot group number (SGN) data were examined for 1997 - 2003 (part of cycle 23) and compared with data for coronal mass ejection (CME) events. It was noticed that they exhibite…
Sources of SEP Acceleration during a Flare - CME Event
Vainio, R.; Valtonen, E.; Huttunen-Heikinmaa, K. +3 more
A high-speed, halo-type coronal mass ejection (CME), associated with a GOES M4.6 soft X-ray flare in NOAA AR 0180 at S12W29 and an EIT wave and dimming, occurred on 9 November 2002. A complex radio event was observed during the same period. It included narrow-band fluctuations and frequency-drifting features in the metric wavelength range, type II…
Do Photospheric Brightness Structures Outside Magnetic Flux Tubes Contribute to Solar Luminosity Variation?
Bernasconi, Pietro N.; Foukal, Peter
Variations in total solar irradiance (TSI) correlate well with changes in projected area of photospheric magnetic flux tubes associated with dark sunspots and bright faculae in active regions and network. This correlation does not, however, rule out possible TSI contributions from photospheric brightness inhomogeneities located outside flux tubes …
Instrumental Response Function for Filtergraph Instruments
Wachter, R.
Dopplergrams and magnetograms arising from filtergraph instruments such as the Michelson Doppler Imager (MDI), the Helioseismic and Magnetic Imager (HMI), or the Hinode Narrow Band Filter Imager are generally associated with observation heights that are derived from the contribution function of the targeted absorption line, irrespective of the ins…
Visualization of Distributed Solar Data and Metadata with the Solar Weather Browser
Berghmans, D.; Nicula, B.; Marqué, C.
The Solar Weather Browser (SWB) is a standalone, open-source software tool designed to display solar images with context overlays. It was originally developed for the space-weather forecast activities of the Solar Influence Data analysis Center (SIDC) but it is more generally well suited to display the output of solar-feature recognition methods. …
Spatio-Temporal Analysis of Photospheric Turbulent Velocity Fields Using the Proper Orthogonal Decomposition
Vecchio, A.; Carbone, V.; Veltri, P. +4 more
The spatio-temporal dynamics of the solar photosphere are studied by performing a proper orthogonal decomposition (POD) of line-of-sight velocity fields computed from high-resolution data coming from the SOHO/MDI instrument. Using this technique, we are able to identify and characterize the different dynamical regimes acting in the system. All of …
EIS/ Hinode Observations of Doppler Flow Seen through the 40-Arcsec Wide-Slit
Madjarska, M. S.; Innes, D. E.; Hara, H. +1 more
The Extreme ultraviolet Imaging Spectrometer (EIS) onboard Hinode is the first solar telescope to obtain wide-slit spectral images that can be used for detecting Doppler flows in transition region and coronal lines on the Sun and to relate them to their surrounding small-scale dynamics. We select EIS lines covering the temperature range 6×104…
Similarities and Dissimilarities between the Variations of CME and Other Solar Parameters at Different Heliographic Latitudes and Time Scales
Kane, R. P.
From the LASCO CME (Coronal Mass Ejection) catalog, the occurrence frequencies of all CMEs (all strong and weak CMEs, irrespective of their widths) were calculated for 3-month intervals and their 12-month running means determined for cycle 23 (1996 - 2007) and were compared with those of other solar parameters. The annual values of all-CME frequen…