Search Publications
ULYSSES at high latitudes: an overview of recent results
Smith, E. J.; Marsden, R. G.
After its fly-by of the planet Jupiter in February 1992, the Ulysses spacecraft is now in a highly inclined heliocentric orbit that will bring it above the south polar regions of the Sun in September 1994. The high-latitude phenomena observed to date have been strongly influenced by the near-minimum solar activity conditions encountered during thi…
Wave field analysis by magnetic measurements at satellite arrays: generalized minimum variance analysis
Glassmeier, K. H.; Motschmann, U.; Southwood, D. J. +1 more
The main goal of the CLUSTER mission with four identical spacecraft is the spatial resolution of plasma structures. For the determination of the wave vectors of a wave field from four positions classical Fourier analysis is inappropriate. We develop a generalized minimum variance technique which gives a high wave vector resolution though the spati…
ULYSSES observations of double ion beams associated with coronal mass ejections
Balogh, A.; Phillips, J. L.; Feldman, W. C. +1 more
Coronal mass ejections (CME's) are thought to result from the loss of stability within a magnetically confined coronal structure leading to its radial expansion into interplanetary space. As the CME expands into the corona current sheets will form between the expanding CME and surrounding field lines in the ambient wind. This configuration may lea…
Analysis of non-planar structures with multipoint measurements
Balogh, A.; Dunlop, M. W.; Motschmann, U. +2 more
The advent of multi-spacecraft space missions like CLUSTER provides a new challenge for maximising the information return from data taken of complex magnetic field structures in the Earth's plasma environment using a spacecraft magnetometer. Most challenging are those structures which are not amenable to single spacecraft analysis techniques such …
Taurid complex meteoroids detected near aphelion with ULYSSES
Grün, E.; McDonnell, J. A. M.; Taylor, A. D.
Between 3.4 and 4.0 AU the dust detection system aboard the Ulysses spacecraft showed an increase in detection rate for particles with masses greater than 5 x 10^-13 g. The spacecraft meteoroid encounter geometry indicates highly eccentric orbits detected near aphelion. The outer limit of the enhanced flux is imposed as meteoroids on such orbits m…
Non-thermal velocities in flare plasmas
Benna, C.; Antonucci, E.; Martin, R. +1 more
The analysis of the profile and intensity of the soft X-ray lines formed in the wavelength range from 1.8 Angstroms to 20 Angstroms, observed with the Soft X-ray Polychromator of the Solar Maximum Mission (SMM), shows that solar flare plasmas are characterized by non-thermal velocities. Flare plasmas in general consist of two components at differe…
Coronal transport and storage of energetic particles
Simnett, G. M.
There is increasing evidence that regions of the corona or the inner heliosphere sometimes impede the escape of energetic particles accelerated at the Sun. Certain impulsive radio, X- and gamma-ray emissions indicate times at which major particle acceleration has recently occurred. The more gradual emissions are harder to interpret, and may reflec…
Interplanetary magnetic field control of heavy ion abundances at ~ 5.2 AU
Forsyth, R. J.; Lanzerotti, L. J.; Maclennan, C. G.
The HI-SCALE instrument on the Ulysses spacecraft measured a long-lasting heavy ion particle event from about day 304 to day 318, 1992, at a southern heliographic latitude of ~20 deg. An analysis is presented of the relative (to O) C and Fe abundance variations during this interval. The variations are associated with major interplanetary magnetic …
Transport of energetic particles derived from a detailed analysis of the September 29, 1989 solar flare
Vainio, R.; Torsti, J.; Anttila, A. +1 more
The exceptionally energetic flare of September 29, 1989, at 11:33 UT has been analyzed using neutron monitor data and the energy resolved particle data collected by the GOES satellites. A picture emerges of a dual injection in the impulsive, explosive phase of the flare process, with an additional gradual source mechanism traced to the shock front…