Search Publications
Distinct shock acceleration processes — Evaluation of the magnetic trap dimensions formed upstream of an interplanetary shock using measurements of the ulysses spacecraft
Sarris, E. T.; Anagnostopoulos, G. C.; Marhavilas, P. K. +1 more
We analyze the acceleration signatures of energetic ions (E > 50 keV) and electrons (E > 30 keV) being observed on day 256 of the year 1992 UT, in the vicinity of the surface of a fast-mode quasi-perpendicular interplanetary hydromagnetic shock, using fine time resolution measurements by the HI-SCALE instrument onboard the Ulysses spacecraft…
How directions and helicity of erupted solar magnetic fields define geoeffectiveness of coronal mass ejections
Wang, Haimin; Yurchyshyn, Vasyl; Abramenko, Valentyna
In this study we report on the relationship between the projected speed of CMEs, measured at 20R from SOHO/LASCO images, and the hourly averaged magnitude of the southwardly directed magnetic field, B z, at the leading edge of interplanetary ejecta, as measured by the ACE magnetometer. We found that those CMEs that originate at the cent…
Heliospheric Langmuir wave observations from the Ulysses spacecraft
McComas, D. J.; Lin, Naiguo; MacDowall, R. J.
Langmuir waves are electrostatic plasma oscillations produced by unstable electron beams in the solar wind and elsewhere. Typical electron sources are solar flares, shocks, and magnetic holes. In this paper, we present an overview of the Langmuir waves observed by Ulysses during both its solar minimum and solar maximum orbits. Langmuir waves in ma…
The metallicity of β Cephei stars on the basis of the satellite ultraviolet spectra
Niemczura, E.; Cugier, H.; Daszyńska, J.
We derive the mean stellar parameters like angular diameter, effective temperature, and metallicity from ultraviolet spectra for all β Cephei stars observed during the IUE satellite mission, including those belonging to the three open clusters. For this purpose we fit the theoretical flux distributions of Kurucz's models to observed low-resolution…
Quiet time MEV electron increases at solar maximum: Ulysses cospin/ket observations
Fichtner, H.; Kunow, H.; Wibberenz, G. +10 more
The Ulysses trajectory provides a unique opportunity to study the propagation of MeV electrons in a wide range of heliographic latitudes and during varying conditions in the inner heliosphere. In recent papers we reported Ulysses Kiel Electron Telescope (KET) observations from the Ulysses launch up to the end of the second fast latitude scan in la…
Continuous tracking of CMEs using MICA, and LASCO C2 and C3 coronagraphs
Schwenn, R.; Stenborg, G.; Balmaceda, L. +3 more
In this work we have tracked coronal mass ejections observed with the ground based Mirror Coronagraph for Argentina (MICA) and the Large Angle and Spectroscopic Coronagraph (LASCO) C2 and C3 on board of the Solar and Heliospheric Observatory (SOHO). The MICA telescope is located at El Leoncito (31.8 S, 69.3 W), San Juan (Argentina), since 1997 as …
Coronal loops: Isothermal OR multithermal?
Schmelz, J. T.; Cirtain, J. W.; Beene, J. E. +5 more
Are coronal loops isothermal? A controversy over this question has arisen recently because different investigators using different techniques have obtained very different answers. Analysis of data using narrowband filter ratios to obtain temperature maps has produced several key publications that suggest that coronal loops may be isothermal. We ha…
Coronal densities and temperatures for cool stars in different stages of activity
Schmitt, J. H. M. M.; Audard, M.; Güdel, M. +1 more
With the advent of the new X-ray missions Chandra and XMM-Newton, high-resolution spectroscopy has become available for studies of stellar coronae. Individual lines can be used as diagnostic tools for measuring densities and temperatures in coronal plasma. In addition to the overall X-ray luminosity, spectroscopic properties can be used for a clas…
Peak proton intensities and composition variations of heavy ions during large solar energetic particle events: Uleis observations
Gold, R. E.; Roelof, E. C.; Ho, G. C. +2 more
We have examined low energy proton and heavy ion intensities in large solar energetic particle (SEP) events from 1997 to the end of 2001 using the ULEIS instrument on ACE spacecraft. We selected 33 events that are isolated and show clear onsets at 1 AU. The optical and radio signatures for all of our events are identified and where data are availa…
Experimental studies of wave-particle interactions in space using particle correlators: Results and future developments
Gough, M. P.; Buckley, A. M.; Carozzi, T. +1 more
The technique of particle correlation measures directly electron modulations that result from naturally occurring and actively stimulated wave-particle interactions in space plasmas. In the past this technique has been used for studies of beam-plasma interactions, caused by both natural auroral electron beams via sounding rockets and by artificial…