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First Energetic Particle Events Observed by the ERNE Instrument
Laitinen, T.; Vainio, R.; Valtonen, E. +6 more
The energetic particle instrument ERNE on-board SOHO started its observations on December 15, 1995. The low-energy sensor of ERNE, LED, is capable of measuring particles in the energy range from 1 to 10 MeV nucl-1. From the beginning of the year 1996 until May 22, 1996, LED-observations included four energetic particle events above thre…
Study of Coronal Transients in UV Line Emission
Noci, Giancarlo; Martin, Renato; Maccari, Lisa
We investigate the expected emission from coronal transients in the following spectral lines observable with the Ultraviolet Coronagraph Spectrometer (UVCS) on board SOHO: Hi Lα 1216 Å, Ovi 1032-1037 Å, Nv 1239-1243 Å, Mgx 610-625 Å, Sixii 499-521 Å, and Fexii 1242 Å. We calculate line intensities and profiles for typical CME conditions, and we an…
Solar and heliospheric plasma physics. Proceedings. 8th European Solar Physics Meeting, Halkidiki (Greece), 13 - 18 May 1996.
Heinzel, P.; Simnett, G.
The main topic was the interaction of the Sun with the heliosphere, focused on first results from SOHO and new results from Ulysses. The following topics were dealt with: solar dynamos, solar shape, convection zone, solar pulsations, solar activity, solar atmosphere, solar corona, solar spectra, solar prominences, solar flares, UV spectra, solar w…
Inferences on Coronal Magnetic Fields from SOHO UVCS Observations
Romoli, M.; Wu, S. T.; Poletto, G. +2 more
The characteristics of the magnetic field ubiquitously permeating the coronal plasma are still largely unknown. In this paper we analyze some aspects of coronal physics, related to the magnetic field behavior, which forthcoming SOHO UVCS observations can help better understand. To this end, three coronal structures will be examined: streamers, cor…
Oblique Emission of Whistler-Mode Waves around Interplanetary Shocks
Balogh, A.; Forsyth, R. J.; Scime, E. E. +4 more
We present a study of whistler-mode wave generation and wave particle interaction in the vicinity of interplanetary shocks as observed by the Ulysses spacecraft. Generally the whistler-mode waves (measured in the frequency range 0.22-448 Hz) are observed downstream of the shocks where they persist for some hours. From the electron distribution fun…
The 1990 May 24 Solar Cosmic-Ray Event
Vainio, R.; Torsti, J.; Anttila, A. +2 more
This paper presents an integrated analysis of GOES 6, 7 and neutron monitor observations of solar cosmic-ray event following the 1990 May 24 solar flare. We have used a model which includes particle injection at the Sun and at the interplanetary shock front and particle propagation through the interplanetary medium. The model does not attempt to s…
A Joint Analysis of High-Energy Neutrons and Neutron-Decay Protons from a Flare
Vainio, R.; Torsti, J.; Usoskin, I. G. +2 more
A joint analysis of neutron monitor and GOES data is performed to study the production of high-energy neutrons at the Sun. The main objects of the research are the spectrum of >50 MeV neutrons and a possible spectrum of primary (interacting) protons which produced those neutrons during the major 1990 May 24 solar flare. Different possible scena…
Stochastic Wave Growth, Power Balance, and Beam Evolution in Type III Solar Radio Sources
Robinson, P. A.
Energy-balance arguments are combined with the stochastic-growth theory of type III radio sources to determine the properties of the source in average dynamical equilibrium with the beam, and the beam's long-term evolution. Purely linear stochastic-growth theory has previously emphasized that the beam evolves to a state close to marginal stability…
A 2D Numerical Study of Explosive Events in the Solar Atmosphere
Inhester, B.; Innes, D.; Jin, S. -P.
Two-dimensional (2D) compressible magnetohydrodynamic simulations are performed to explore the idea that the asymmetric reconnection between newly emerging intranetwork magnetic field flux and pre-existing network flux causes the explosive events in the solar atmosphere. The dependence of the reconnection rate as a function of time on the density …
Theoretical Plasma Distributions Consistent with ULYSSES Magnetic Field Observations in a Solar Wind Tangential Discontinuity
Tsurutani, B. T.; Roth, M.; De Keyser, J. +3 more
The overall multi-layer structure of the magnetic field profile observed by Ulysses across a broad solar wind tangential discontinuity can be reproduced fairly well by means of a kinetic model. Such a simulation provides complementary information about the velocity distribution functions, which are not always available from the plasma experiment d…