Solar and Heliospheric Observatory/Large Angle Spectrometric Coronagraph Polarimetric Calibration

Solar Physics ◽  
2006 ◽  
Vol 237 (1) ◽  
pp. 211-222 ◽  
Author(s):  
Thomas G. Moran ◽  
Joseph M. Davila ◽  
Jeff S. Morrill ◽  
Dennis Wang ◽  
Russel Howard
1998 ◽  
Vol 11 (2) ◽  
pp. 861-864
Author(s):  
K. P. Dere ◽  
G. E. Brueckner

The combined operations of the Large Angle Spectrometric Coronagraph (LASCO) and the Extreme Ultraviolet Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO), launched in December 1995, have provided an unprecedented opportunity for observing essentially all coronal phenomena that are not hidden behind the disk of the Sun. Consequently, observations with these instrument are providing information on coronal mass ejections (CMEs) from their initiation through their development over 30 ⊙. They reveal a coronal that never reaches a steady state. The corona is the site of continuous, time-dependent outflows, both within the coronal holes and the high speed streams and in the streamer belts and their mid-latitude sources. The spatial scales of these outflows range from 10s of arc-seconds through about a solar radius in large CMEs.


2008 ◽  
Vol 4 (S257) ◽  
pp. 233-243 ◽  
Author(s):  
Seiji Yashiro ◽  
Nat Gopalswamy

AbstractWe report on the statistical relationships between solar flares and coronal mass ejections (CMEs) observed during 1996-2007 inclusively. We used soft X-ray flares observed by the Geostationary Operational Environmental Satellite (GOES) and CMEs observed by the Large Angle and Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric Observatory (SOHO) mission. Main results are (1) the CME association rate increases with flare's peak flux, fluence, and duration, (2) the difference between flare and CME onsets shows a Gaussian distribution with the standard deviation σ = 17 min (σ = 15 min) for the first (second) order extrapolated CME onset, (3) the most frequent flare site is under the center of the CME span, not near one leg (outer edge) of the CMEs, (4) a good correlation was found between the flare fluence versus the CME kinetic energy. Implications for flare-CME models are discussed.


2000 ◽  
Vol 39 (22) ◽  
pp. 3955 ◽  
Author(s):  
Maurice Bout ◽  
Philippe Lamy ◽  
André Maucherat ◽  
Claude Colin ◽  
Antoine Llebaria

2000 ◽  
Vol 534 (1) ◽  
pp. 456-467 ◽  
Author(s):  
A. Vourlidas ◽  
P. Subramanian ◽  
K. P. Dere ◽  
R. A. Howard

2008 ◽  
Vol 26 (10) ◽  
pp. 3067-3075 ◽  
Author(s):  
G. Poletto ◽  
A. Bemporad ◽  
F. Landini ◽  
M. Romoli

Abstract. This paper aims at studying reconnection occurring in the aftermath of the 28 May 2004, CME, first imaged by the LASCO (Large Angle and Spectrometric Coronagraph) C2 at 11:06 UT. The CME was observed in White Light and UV radiation: images acquired by the LASCO C2 and C3 coronagraphs and spectra acquired by UVCS (Ultraviolet Coronagraph Spectrometer) allowed us to identify the level at which field lines, stretched outwards by the CME ejection, reconnect below the CME bubble. As the CME propagates outwards, reconnection occurs at increasingly higher levels. The process goes on at a low pace for several hours: here we give the profile of the reconnection rate vs. heliocentric distance over a time interval of ≈14 h after the CME onset, extending estimates of the reconnection rate to larger distances than previously inferred by other authors. The reconnection rate appears to decrease with time/altitude. We also calculate upper and lower limits to the density in the diffusion region between 4 and 7 R⊙ and conclude by comparing estimates of the classical and anomalous resistivity in the diffusion region with the value inferred from the data. The latter turns out to be ≥5 order of magnitudes larger than predicted by classical or anomalous theories, pointing to the need of identifying the process responsible for the observed value.


1999 ◽  
Vol 523 (1) ◽  
pp. 444-449 ◽  
Author(s):  
B. E. Wood ◽  
M. Karovska ◽  
J. W. Cook ◽  
R. A. Howard ◽  
G. E. Brueckner

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