Search Publications
Analysis of thick, non-planar boundaries using the discontinuity analyser
Dunlop, M. W.; Woodward, T. I.
The advent of missions comprised of phased arrays of spacecraft, with separation distances ranging down to at least mesoscales, provides the scientific community with an opportunity to accurately analyse the spatial and temporal dependencies of structures in space plasmas. Exploitation of the multi-point data sets, giving vastly more information t…
The structure and origin of magnetic clouds in the solar wind
Schwenn, R.; Bothmer, V.
Plasma and magnetic field data from the Helios 1/2 spacecraft have been used to investigate the structure of magnetic clouds (MCs) in the inner heliosphere. 46 MCs were identified in the Helios data for the period 1974-1981 between 0.3 and 1 AU. 85% of the MCs were associated with fast-forward interplanetary shock waves, supporting the close assoc…
Long-duration high-energy proton events observed by GOES in October 1989
Vainio, R.; Torsti, J.; Anttila, A. +1 more
We consider the prolonged injection of the high-energy (>10 MeV) protons during the three successive events observed by GOES in October 1989. We apply a solar-rotation-stereoscopy approach to study the injection of the accelerated particles from the CME-driven interplanetary shock waves in order to find out how the effectiveness of the particle…
What causes the variations of the peak intensity of CIR accelerated energetic ion fluxes?
Keppler, E.
The variation of the peak intensity of energetic ions accelerated at CIR related shocks in the interplanetary medium as observed by instruments on board of ULYSSES during its pass towards the south polar region and from the north polar region back to its aphelium is discussed. From ULYSSES measurements alone it cannot be decided whether the observ…
Non-spherical source-surface model of the heliosphere: a scalar formulation
Schulz, M.
The source-surface method offers an alternative to full MHD simulation of the heliosphere. It entails specification of a surface from which the solar wind flows normally outward along straight lines. Compatibility with MHD results requires this (source) surface to be non-spherical in general and prolate (aligned with the solar dipole axis) in prot…
Determination of interstellar pickup ion distributions in the solar wind with SOHO and Cluster
Möbius, E.; Lee, M. A.; Rucinski, D. +1 more
Over the last 10 years, the experimental basis for the study of the local interstellar medium has been substantially enhanced by the direct detection of interstellar pickup ions and of interstellar neutral helium within the heliosphere. Pickup ions can be studied for a wide range of interstellar species. However, currently the accuracy of the meth…
ULYSSES observations of energetic particle acceleration and the superposed CME and CIR events of November 1992
Forsyth, R. J.; Keppler, E.; Kunow, H. +4 more
During November 1992, a series of forward and reverse shocks passed the ULYSSES spacecraft. Spectral and anisotropy measurements are reported for protons and alpha particles between 0.28 and 6 MeV observed by the Energetic Particle Composition Experiment, data recorded by the Magnetometer Experiment and the high-energy (2.7-300 MeV) proton data fr…
Recurrent variations of anomalous oxygen in association with a corotating interaction region
Fränz, M.; Keppler, E.; Reuss, M. K.
The fluxes of anomalous oxygen (E ranging from 3.5-6.8 MeV/amu), as measured by the EPAC instrument on ULYSSES, show a recurrent variation with the solar rotation period, which is anticorrelated with the fluxes of particles accelerated at the shocks of a corotating interaction region (CIR), and correlated with the fluxes of galactic cosmic rays kn…
Performance of ERNE in particle flux anisotropy measurement
Valtonen, E.; Lumme, M.; Riihonen, E. +3 more
The HED particle detector of the ERNE experiment to be flown on the SOHO spacecraft is unique compared to the earlier space-born detectors in its high directional resolution (better than 2°, depending on the track inclination). Despite the fixed view cone due to the three-axis stabilization of the spacecraft, the good angular and temporal resoluti…
Energetic particle investigation using the ERNE instrument
Vainio, R.; Valtonen, E.; Eronen, T. +9 more
During solar flares and coronal mass ejections, nuclei and electrons accelerated to high energies are injected into interplanetary space. These accelerated particles can be detected at the SOHO satellite by the ERNE instrument. From the data produced by the instrument, it is possible to identify the particles and to calculate their energy and dire…