Search Publications
Continuous tracking of coronal outflows: Two kinds of coronal mass ejections
Howard, R. A.; Sheeley, N. R.; Wang, Y. -M. +1 more
We have developed a new technique for tracking white-light coronal intensity features and have used this technique to construct continuous height/time maps of coronal ejecta as they move outward through the 2-30Rs field of view of the Large-Angle Spectrometric Coronagraph (LASCO) on the Solar and Heliospheric Observatory (SOHO) spacecra…
SOHO/EIT Observations of the 1997 April 7 Coronal Transient: Possible Evidence of Coronal Moreton Waves
Michels, D. J.; Thompson, B. J.; Gurman, J. B. +7 more
We report observations obtained with the Extreme ultraviolet Imaging Telescope (EIT) on board SOHO of a large-scale coronal transient propagating across the disk of the Sun at a speed of 250 km s-1, in apparent association with a flare and coronal mass ejection. The observations consist of a series of images taken in the Fe XII 195 Å ba…
Magnetohydrodynamic modeling of the solar corona during Whole Sun Month
Thompson, B. J.; Forsyth, R. J.; Biesecker, D. A. +7 more
The Whole Sun Month campaign (August 10 to September 8, 1996) brought together a wide range of space-based and ground-based observations of the Sun and the interplanetary medium during solar minimum. The wealth of data collected provides a unique opportunity for testing coronal models. We develop a three-dimensional magnetohydrodynamic (MHD) model…
An Empirical Model of a Polar Coronal Hole at Solar Minimum
Romoli, M.; Raymond, J. C.; Naletto, G. +28 more
We present a comprehensive and self-consistent empirical model for several plasma parameters in the extended solar corona above a polar coronal hole. The model is derived from observations with the SOHO Ultraviolet Coronagraph Spectrometer (UVCS/SOHO) during the period between 1996 November and 1997 April. We compare observations of H I Lyα and O …
On the Doppler Shifts of Solar Ultraviolet Emission Lines
Peter, H.; Judge, P. G.
We examine emission-line profiles observed with the Solar Ultraviolet Measurement of Emitted Radiation (SUMER) instrument during the roll of the SOHO spacecraft on 1997 March 20. SUMER data were acquired in selected wavelength bands including lines from the low chromosphere to the corona. Our main aim is to determine the center-to-limb behavior of…
Solar Wind Outflow and the Chromospheric Magnetic Network
Dammasch, Ingolf E.; Wilhelm, Klaus; Curdt, Werner +5 more
Spectroscopic Constraints on Models of Ion Cyclotron Resonance Heating in the Polar Solar Corona and High-Speed Solar Wind
Kohl, John L.; Cranmer, Steven R.; Field, George B.
Using empirical ion velocity distributions derived from Ultraviolet Coronagraph Spectrometer (UVCS) and Solar Ultraviolet Measurements of Emitted Radiation (SUMER) ultraviolet spectroscopy, we construct theoretical models of the nonequilibrium plasma state of the polar solar corona. The primary energy deposition mechanism we investigate is the dis…
Three-dimensional Stereoscopic Analysis of Solar Active Region Loops. I. SOHO/EIT Observations at Temperatures of (1.0-1.5) × 106 K
Klimchuk, J. A.; Aschwanden, Markus J.; Gary, G. Allen +5 more
The three-dimensional structure of solar active region NOAA 7986 observed on 1996 August 30 with the Extreme-Ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory (SOHO) is analyzed. We develop a new method of dynamic stereoscopy to reconstruct the three-dimensional geometry of dynamically changing loops, which allows…
Slow Magnetosonic Waves in Coronal Plumes
Nakariakov, V. M.; DeForest, C. E.; Ofman, L.
Recent observations of polar plumes in the southern solar coronal hole by the Extreme-Ultraviolet Imaging Telescope (EIT) on board the SOHO spacecraft show signatures of quasi-periodic compressional waves with periods of 10-15 minutes. The relative wave amplitude was found to increase with height in the plumes up to about 1.2 Rsolar. Us…
Active region EUV transient brightenings - First Results by EIT of SOHO JOP 80
Berghmans, D.; Clette, F.
On 13 May 1998, the Extreme-Ultraviolet Imaging Telescope (EIT, on board SOHO) has produced a unique image sequence operating in 'shutterless mode' (SOHO JOP 80). In JOP 80, EIT is the lead instrument, followed by several space-born instruments (SXT, TRACE, MDI, CDS, SUMER), as well as two observatories on the ground (in La Palma and Sac Peak). Th…