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…
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…
Solar minimum streamer densities and temperatures using Whole Sun Month coordinated data sets
Bagenal, F.; Fludra, A.; Gibson, S. E. +3 more
We model electron densities of the simplest, most symmetric solar minimum streamer structure observed during the Whole Sun Month (WSM) campaign, using coronal observations of both visible white light and extreme ultraviolet (EUV) emission. Using white light data from the SOHO/LASCO/C2 and HAO/Mauna Loa Mark 3 coronagraphs, we determine electron de…
Heating and cooling of protons by turbulence-driven ion cyclotron waves in the fast solar wind
Li, Xing; Habbal, Shadia R.; Hollweg, Joseph V. +1 more
The effects of parallel propagating nondispersive ion cyclotron waves on the solar wind plasma are investigated in an attempt to reproduce the observed proton temperature anisotropy, namely, Tp⊥>>Tp∥ in the inner corona and Tp⊥<Tp∥ at 1 AU. Low-frequency Alfvén waves are assumed to carry most of…
Physical properties of a coronal hole from a coronal diagnostic spectrometer, Mauna Loa Coronagraph, and LASCO observations during the Whole Sun Month
Fludra, A.; Gibson, S. E.; Biesecker, D. +2 more
Until recently [Guhathakurta and Fisher, 1998], inference of electron density distribution in the solar corona was limited by the field of view of white-light coronagraphs (typically out to 6 Rs). Now, for the first time we have a series of white-light coronagraphs (SOHO/LASCO) whose combined field of view extends from 1.1-30 Rs
Electron density and temperature of the lower solar corona
Del Zanna, G.; Fludra, A.; Bromage, B. J. I. +1 more
Off limb observations of the quiet Sun corona were made with the Coronal Diagnostic Spectrometer (CDS) on SOHO during the Whole Sun Month campaign in August 1996. Selected spectral lines in the Normal Incidence range were recorded up to 1.2 solar radii above the east and west limb and above the polar coronal holes. Intensities of the coronal lines…
The Elephant's Trunk: Spectroscopic diagnostics applied to SOHO/CDS observations of the August 1996 equatorial coronal hole
Del Zanna, G.; Bromage, B. J. I.
A large equatorial coronal hole, named the ``Elephant's Trunk,'' was observed by the coronal diagnostic spectrometer (CDS) on board the Solar and Heliospheric Observatory (SOHO) during the last week of August 1996. Spatially averaged spectra within the hole and in neighboring quiet sun regions are analyzed and calibrated in intensity. Spectroscopi…
Radio signatures of a fast coronal mass ejection development on November 6, 1997
Schwenn, R.; Pick, M.; Vourlidas, A. +3 more
The Oporto radiospectrograph and the Nançay radioheliograph recorded a radio event on November 6, 1997, closely related in time with a flare on National Oceanic and Atmospheric Administration (NOAA) active region 8100. At the beginning of the event the radio sources are located on a rather small volume in the vicinity of the flare site. In a times…
Cyclotron resonance in coronal holes: 1. Heating and acceleration of protons, O5+, and Mg9+
Hollweg, Joseph V.
The resonant heating and acceleration of protons and selected heavy ions in coronal holes are investigated by calculating trajectories of individual test particles under the influence of gravity, the electrostatic electric field, the mirror force, and the resonant acceleration due to interaction with dispersive ion cyclotron waves. The transverse …
Interplanetary Lyman α line profiles derived from SWAN/SOHO hydrogen cell measurements: Full-sky Velocity Field
Bertaux, Jean-Loup; Lallement, Rosine; Quémerais, Eric +3 more
We present here an analysis of 1 year of data obtained by the solar wind anisotropies (SWAN) instrument on board the SOHO spacecraft orbiting around the L1 Lagrange point at 1.5×106km sunward from Earth. This instrument is measuring the interplanetary Lyman α background due to solar photons backscattered by hydrogen atoms in the interpl…