Search Publications
Comparison of GONG and MDI solar p-mode background
Hill, F.; Barban, C.
Using Severino's model, we estimate the amount of coherent correlated and uncorrelated background and incoherent noise components needed to reproduce the following four helioseismic spectra: V power, I power, V-I phase difference and V-I coherence, using GONG and MDI data. We confirm that a coherent correlated component of 10-15% of the total back…
Absolute Accuracy and Repeatability of the Rmib Radiometers for Tsi Measurements
Mekaoui, Sabri; Dewitte, Steven; Conscience, Christian +3 more
Radiometers for the measurement of the total solar irradiance from space have been developed by D. Crommelynck at the Royal Meteorological Institute of Belgium (RMIB) since 1970. These radiometers, also used in the set of instruments defining the "World Radiometric Reference", have successively flown on SPACELAB 1, ATLAS 1, EURECA, ATLAS 2, ATLAS …
Multi-Wavelength Analysis of the 29 September 2002 M2.6/2N Flare
Dzifčáková, Elena; Karlický, Marian; Kulinová, Alena +1 more
Using TRACE EUV 171 Å line, Hα line, Zürich radio, RHESSI, and HXRS observations the 29 September 2002 flare (M2.6), which occurred in AR NOAA 0134, was analyzed. Flaring structures were compared with a potential magnetic field model (field lines and quasi-separatrix layers) made from SOHO/MDI full-disk magnetogram. Series of high-resolution SOHO/…
Observations of CME-related phenomena in a wide spectral range
Grechnev, V. V.; Uralov, A. M.; Borovik, V. N. +7 more
We study pre-eruptive, eruptive, and post-eruptive phenomena related to a CME that occurred on November 23, 2000 by means of joint analyses of data from various spectral ranges. Almost all known CME-associated phenomena were observed during this event, i.e., a filament eruption, solar flare, dimmings, and a post-eruptive arcade formation. Followin…
Re-Evaluation of the Flare Type II CME Association
Kim, Y. -H.; Moon, Y. -J.; Shanmugaraju, A. +2 more
We have re-evaluated the association of type II solar radio bursts with flares and/or coronal mass ejections (CMEs) using the year 2000 solar maximum data. For this, we consider 52 type II events whose associations with flares or CMEs were absent or not clearly identified and reported. These events are classified as follows; group I: 11 type IIs f…
A comparison of the use of genetic and hill-climbing algorithms to fit low-l solar p-mode spectra
Chaplin, W. J.; Elsworth, Y.; Fletcher, S. T.
We present a comparative study of low-l solar p-mode parameters extracted by genetic-algorithm and `standard' hill-climbing minimisation routines. To effect this we make use of observations made in integrated sunlight by the Birmingham Solar-Oscillations Network (BiSON) and the GOLF instrument on board the ESA/NASA SOHO satellite, in addition to a…
Photospheric and heliospheric magnetic fields
Schrijver, Carolus J.; De Rosa, Marc L.
The magnetic field in the heliosphere evolves in response to the photospheric field at its base. This evolution, together with the rotation of the Sun, drives space weather through the continually changing conditions of the solar wind and the magnetic field embedded within it. We combine observations and simulations to investigate the sources of t…
Observations of Rotating Sunspots from TRACE
Schrijver, C. J.; Shine, R. A.; Title, A. M. +5 more
Recent observations from TRACE in the photospheric white-light channel have shown sunspots that rotate up to 200° about their umbral centre over a period of 3-5 days. The corresponding loops in the coronal fan are often seen to twist and can erupt as flares. In an ongoing study, seven cases of rotating sunspots have been identified, two of which c…
Weak-Field Magnetogram Calibration using Advanced Stokes Polarimeter Flux Density Maps - II. SOHO/MDI Full-Disk Mode Calibration
Lites, B. W.; Berger, T. E.
Cotemporal Ni i 676.8 nm full-disk magnetograms from the Michelson Doppler Interferometer (MDI) instrument on SOHO and the Advanced Stokes Polarimeter (ASP) are quantitatively compared using observations of active region AR 8218, a large negative polarity sunspot group observed at S20 W22 on 13 May 1998. MDI produces flux density estimates based o…
A Search for CMEs Associated with Big Flares
Andrews, M. D.
The relationship between flares and coronal mass ejections (CMEs) remains a topic of active research. This paper considers a complete set of 311 M- and X-class GOES soft X-ray flares observed during the years 1996-1999. The durations of these flares have been determined as part of this study. Possible CME candidates for the 229 flares with good LA…