Search Publications
A two-Type Classification of Lasco Coronal Mass Ejection
Andrews, M. D.; Howard, R. A.
The causes and origins of Coronal Mass Ejections (CMEs) remain among the outstanding questions in Space Physics. The observations of CMEs by the LASCO coronagraphs on SOHO suggest that there are two distinct types of CMEs. The two types of events can be most easily distinguished by examining height-time plots. The Type A (Acceleration) events prod…
Heating of Coronal Holes and Generation of the Solar Wind by Ion-Cyclotron Resonance
Isenberg, Philip A.
We discuss a new model to describe the heating of the magnetically open solar corona and the acceleration of the fast solar wind by the cyclotron resonant interaction of coronal ions with ion-cyclotron waves. This `kinetic shell' model includes important details of the wave-particle interaction which are not present in most other treatments. In th…
Numerical Magnetohydrodynamic (MHD) Modeling of Coronal Mass Ejections (CMEs)
Plunkett, S. P.; Wu, S. T.; Andrews, M. D.
The Coronal Mass Ejection (CME) is arguably the most important discovery of solar eruptive phenomena in the 20th century. It is now also recognized that CMEs have great impact on the Earth's environment by inducing geomagnetic storms. Thus, development of simulation models to understand the physical mechanisms of CME initiation and propagation has…
The Fall 2000 and Fall 2001 SOHO-Ulysses Quadratures
Suess, S.; Poletto, G.
SOHO-Ulysses quadrature occurs when their included angle with the Sun is 90°. At these times the same plasma leaving the Sun in the direction of Ulysses can first be remotely analyzed with SOHO and then later be sampled in situ at Ulysses. Quadratures in Fall 2000/2001 are of special interest because Ulysses will be near the south and north heliog…
Solar Wind Composition at Solar Maximum
Bochsler, Peter
Although coronal mass ejections have traditionally been thought to contribute only a minor fraction to the total solar particle flux, and although such events mainly occur in lower heliographic latitudes, the impressive spectacle of eruptions - observed with SOHO/LASCO even at times of solar minimum - indicates that an important part of the low-la…
UVCS Observations of Velocity Shear at Streamer Boundaries in the Corona
Habbal, Shadia Rifai; Woo, Richard; Vial, Jean-Claude
Measurements of the intensities of the Ovi 1032 and 1037 Å spectral lines in the southern solar hemisphere, from 1.5 to 5 R_s, were made with the SOHO Ultraviolet Coronagraph Spectrometer (UVCS) in May 2000 close to solar maximum. The ratio of the intensity of the two oxygen lines is used as a proxy for solar wind velocity in the inner corona. Whi…
Comparison of quiet-Sun radiances measured by CDS and SUMER on SOHO
Solanki, S. K.; Wilhelm, K.; Schühle, U. +6 more
Since the beginning of the SOHO (Solar and Heliospheric Observatory) mission an intercalibration programme was carried out which included simultaneous observations of the EUV instruments CDS (Coronal Diagnostic Spectrometer) and SUMER (Solar Ultraviolet Measurements of Emitted Radiation) of common targets on the quiet Sun. The observations in the …
Coronal Heating and Solar Wind Acceleration: Future Work on Observations
Peter, Hardi
The space-based observatories SOHO and TRACE have shown some very interesting results on the structure and dynamics of the Sun and its atmosphere, e.g., the extremely high ion temperatures or the enormous variability in the corona. But one question is still open to debate: how to use these data to distinguish between different types of physical he…
Observations of the Acceleration of Polar Solar Wind Near Solar Maximum
Simnett, G. M.; Tappin, S. J.; Lyons, M. A.
In a previous paper (Tappin et al., 1999) we used cross-correlation analysis of high-cadence observations with the LASCO coronagraphs to trace the acceleration of the solar wind at low latitudes. In this paper we present a similar analysis carried out over the North pole of the Sun. The observations which were made in March 2000 with the C3 corona…