Search Publications
Propagation of Solar Cosmic Rays: Diffusion versus Focused Diffusion
Vainio, R.; Torsti, J.; Kocharov, L. G. +1 more
This paper is designed to bring to the attention the fact that the effect of focusing of solar energetic particles is always essential as compared with scattering, no matter how small the value of the mean free path may be. That is why, an ordinary (`focusing-free') diffusion approach can not be applied to the solar cosmic ray transport. In the ca…
A `Ulysses' Cosmic-Ray Latitude Gradient Observation and Modulation Models
Keppler, E.; Quenby, J. J.; Drolias, B. +2 more
The `EPAC' instrument on Ulysses is sensitive to relativistic cosmic rays when far from Jupiter and in the absence of energetic solar particles. Measurement of the latitude gradient of these particles, after correction for time variations, has been made for the 1993-1994 south polar pass. The average magnitude of the gradient is about the same or …
Calculating the Plasma Deformation Tensor and Kinetic Vorticity from Magnetic Field Time Series: Applications to the Solar Wind
Moussas, X.; Polygiannakis, J. M.
It is shown that the magnetic induction equation reduces to an autoregressive model equation. Assuming weakly ergodic field variations in steady mean plasma flow, this model permits the estimation of the mean flow deformation tensor, velocity divergence and kinetic vorticity from magnetic field time series. Applications, made to hourly-averaged, i…
The Large Angle Spectroscopic Coronagraph (LASCO)
Llebaria, A.; Michels, D. J.; Koomen, M. J. +12 more
The Large Angle Spectroscopic Coronagraph (LASCO) is a three coronagraph package which has been jointly developed for the Solar and Heliospheric Observatory (SOHO) mission by the Naval Research Laboratory (USA), the Laboratoire d'Astronomie Spatiale (France), the Max-Planck-Institut für Aeronomie (Germany), and the University of Birmingham (UK). L…
The Solar Oscillations Investigation - Michelson Doppler Imager
Kosovichev, A. G.; Hoeksema, J. T.; Scherrer, P. H. +10 more
The Solar Oscillations Investigation (SOI) uses the Michelson Doppler Imager (MDI) instrument to probe the interior of the Sun by measuring the photospheric manifestations of solar oscillations. Characteristics of the modes reveal the static and dynamic properties of the convection zone and core. Knowledge of these properties will improve our unde…
EIT: Extreme-Ultraviolet Imaging Telescope for the SOHO Mission
Michels, D. J.; Gurman, J. B.; Delaboudinière, J. -P. +25 more
The Extreme-ultraviolet Imaging Telescope (EIT) will provide wide-field images of the corona and transition region on the solar disc and up to 1.5 R⊙ above the solar limb. Its normal incidence multilayer-coated optics will select spectral emission lines from Fe IX (171 å), Fe XII (195 å), Fe XV (284 å), and He II (304 å) to provide sensitive tempe…
The SOHO Mission: an Overview
Domingo, V.; Fleck, B.; Poland, A. I.
The Solar and Heliospheric Observatory (SOHO) is a space mission that forms part of the Solar-Terrestrial Science Program (STSP), developed in a collaborative effort by the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). The STSP constitutes the first "cornerstone" of ESA's long-term programme known as "Sp…
SUMER - Solar Ultraviolet Measurements of Emitted Radiation
Vial, J. -C.; Grewing, M.; Wilhelm, K. +13 more
The instrument SUMER - Solar Ultraviolet Measurements of Emitted Radiation is designed to investigate structures and associated dynamical processes occurring in the solar atmosphere, from the chromosphere through the transition region to the inner corona, over a temperature range from 104 to 2 × 106K and above. These observat…
The Coronal Diagnostic Spectrometer for the Solar and Heliospheric Observatory
Mason, H. E.; Harrison, R. A.; Fludra, A. +36 more
The Coronal Diagnostic Spectrometer is designed to probe the solar atmosphere through the detection of spectral emission lines in the extreme ultraviolet wavelength range 150 - 800 å. By observing the intensities of selected lines and line profiles, we may derive temperature, density, flow and abundance information for the plasmas in the solar atm…
The Ultraviolet Coronagraph Spectrometer for the Solar and Heliospheric Observatory
Livi, S.; Romoli, M.; Geiss, J. +37 more
The SOHO Ultraviolet Coronagraph Spectrometer (UVCS/SOHO) is composed of three reflecting telescopes with external and internal occultation and a spectrometer assembly consisting of two toric grating spectrometers and a visible light polarimeter. The purpose of the UVCS instrument is to provide a body of data that can be used to address a broad ra…