Search Publications
Time-Latitudinal Dynamics of Magnetic Fields and the Green Corona Over Three Solar Cycles
Rušin, Vojtech; Minarovjech, Milan; Saniga, Metod
Time-latitudinal distributions of the solar-surface magnetic fields and the green corona (530.3 nm, Fe XIV) intensities in the period 1975 - 2004 are analyzed. Meridional migration maps show that time-varying components consist of both the poleward and equatorward belts over a solar cycle. The green-corona maps are, for the first time, directly co…
A Contribution to the Understanding of Chromospheric Oscillations
Vial, J. -C.; Baudin, F.; Bocchialini, K. +5 more
We present SUMER/SOHO UV measurements of chromospheric oscillations of intensity, velocity, and linewidth observed in C I, S I, O I, and C II lines, which are formed in the altitude range from 1000 km to 2000 km above τ500=1. Oscillations in lines originating at similar altitudes exhibit different behaviors which we discuss in terms of …
Cluster Observations of the Magnetospheric Low-Latitude Boundary Layer and Cusp during Extreme Solar Wind and Interplanetary Magnetic Field Conditions: I. 10 November 2004 ICME
Dandouras, I.; Fazakerley, A. N.; Marghitu, O. +6 more
We present a study of the magnetospheric cusp response to extreme external parameters during passage of the ICME over the Earth on 10 November 2004, based on Cluster observations of the plasma properties inside the low-latitude boundary layer (LLBL)/cusp regions. Two separate events are observed while Cluster is in the dawn sector, 07 - 08 h magne…
The In-Flight Performance of the SOHO/CDS Grazing Incidence Spectrometer
Del Zanna, G.; Kuin, N. P. M.
We present the characteristics, operations history, performance, and calibration of the Grazing Incidence Spectrometer (GIS) of the Coronal Diagnostic Spectrometer onboard SOHO. The GIS sensitivity has been monitored in a direct manner by examining the quiet Sun count rates during 1996 - 2006, nearly a whole solar cycle of observations. Overall, t…
Simulated Annealing and Bayesian Posterior Distribution Analysis Applied to Spectral Emission Line Fitting
Ireland, Jack
Spectral-line fitting problems are extremely common in all remote-sensing disciplines, solar physics included. Spectra in solar physics are frequently parameterized by using a model for the background and the emission lines, and various computational techniques are used to find values to the parameters given the data. However, the most commonly-us…
The Sun - Earth Workshop: A Summary of the Outcome
Culhane, J. L.; Siscoe, G. L.
This special issue includes a set of papers that deal with extended solar activity, the launching of CMEs at the Sun, their propagation through interplanetary space, and the detection and study of the ejecta near Earth and of their interaction with the Earth's magnetic environment. In particular solar events that occurred on 28 October 2003, 6 and…
An M1.5 Flare Triggered by a Multireconnection Process
Romano, P.; Contarino, L.; Zuccarello, F.
We studied the magnetic configuration of active region NOAA 10672, where two different mechanisms seem to contribute to its instability, to the subsequent M1.5 flare, and to a halo CME. The analysis of full-disk SOHO/MDI magnetograms and of WL and 171 Å TRACE images shows in fact that both flux emergence and horizontal displacements of photospheri…
An Attempt to Detect Coronal Mass Ejections in Lyman-α Using SOHO Swan
St. Cyr, O. C.; Bertaux, J. -L.; Yashiro, S. +4 more
In this study, the possibility that coronal mass ejections (CMEs) may be observed in neutral Lyman-α emission was investigated. An observing campaign was initiated for SWAN (Solar Wind ANisotropies), a Lyman-α scanning photometer on board the Solar and Heliospheric Observatory (SOHO) dedicated to monitoring the latitude distribution of the solar w…
Tracking UVCS/SOHO Responsivity with Observations of ζ Tau
Kohl, John L.; Raymond, John C.; Gardner, Larry D. +3 more
We have tracked the spectral responsivity of the ultraviolet channels of the UVCS (Ultraviolet Coronagraph Spectrometer) instrument on SOHO by repeated observations of a stable hot star. We demonstrate first that the ultraviolet spectral irradiance of the Be star ζ Tau (HD 37202) for the 100- to 125-nm wavelength range has been sufficiently consta…
Evolution of a Coronal Loop System
Wiegelmann, T.; Gontikakis, C.; Tziotziou, K. +3 more
The temporal variation of a loop system that appears to be changing rapidly is examined. The analyzed data were obtained on 15 May 1999, with the Transition Region and Coronal Explorer (TRACE) during an observing campaign and consist of observations in the Fe IX/Fe X 171 Å and Fe XII 195 Å passbands taken at a cadence of ∼10 min. The special inter…