Search Publications
Solar modulation of galactic cosmic rays: the 3D heliosphere
Heber, Bernd; Potgieter, Marius S.; Ferrando, Philippe
The cosmic ray flux observed with the Kiel Electron Telescope onboard the Ulysses space probe varies with solar activity as well as with heliospheric position. The Ulysses' fast latitude scan performed in less than one year between September 1994 to August 1995 allowed us to obtain unique data about the latitudinal dependence of cosmic ray fluxes …
Compressive character of low frequency waves driven by newborn ions at comet Grigg-Skjellerup
Coates, A. J.; Belmont, G.; Neubauer, F. M. +2 more
The investigation by Giotto of the environment of comet P/Grigg-Skjellerup has provided a large set of observations on cometary low-frequency waves for a weakly active comet, after the observations at comets P/Giacobini-Zinner and P/Halley. A large amount of waves are observed at frequencies close to the local water group ion cyclotron frequencies…
Cosmic ray latitudinal effects predicted by a three-dimensional drift model
Potgieter, M. S.; Burger, R. A.; Hattingh, M. +1 more
The Ulysses spacecraft measured surprisingly small latitudinal gradients during its first passage through the polar regions of the heliosphere. This is in contrast to predictions made with two-dimensional drift models for A > 0 magnetic polarity epochs during solar minimum modulation conditions. Several modifications to drift models have been i…
Properties of hydromagnetic waves in the polar caps: ulysses
Forsyth, R.; Balogh, A.; Tsurutani, B. T. +3 more
Properties of the large amplitude Alfvén waves which are a dominant feature of the high latitude solar wind have been studied during the pole-to-pole passage of Ulysses. In addition, an effort has begun to identify magnetosonic waves at high latitude in spite of their expected small amplitude and the presence of the large amplitude Alfvén waves. T…
Cosmic ray modulation in a non-spherical heliosphere during solar minimum conditions
Potgieter, M. S.; Haasbroek, L. J.
It is expected that the position of the modulation boundary in the equatorial and polar regions of the heliosphere depends on solar activity and possibly also on the polarity of the heliospheric magnetic field. In general, it can be assumed that the changing outward solar wind pressure causes a dynamic boundary position. Since the solar wind plasm…
Ulysses solar wind plasma observations at high latitudes
McComas, D. J.; Goldstein, B. E.; Bame, S. J. +7 more
Ulysses reached its peak northerly heliolatitude of 80.2 degN on July 31st, 1995, and is now moving towards aphelion at 5.41 AU which it will reach in May, 1998. We summarize measurements from the solar wind plasma experiment, SWOOPS, emphasizing northern hemispheric observations but also providing southern and equatorial results for comparison. T…
Field-aligned particle streaming in the duskside high latitude Jovian magnetosphere
Krupp, N.; Woch, J.; Dougherty, M. K. +7 more
We report on observations of magnetic field and energetic particle data from the Ulysses spacecraft (S/C) inside the Jovian high latitude duskside magnetosphere. We have combined particle data from the EPAC and the HI-SCALE detectors and find evidence for bi-directional streaming of electrons along the magnetic field lines during the entire outbou…
Comet halley's nucleus: A physical interpretation
Keller, H. U.; Thomas, N.
The nucleus of comet Halley was the first to be detected and observed by cameras on board spacecraft during the fly-bys in 1986. The interpretation of both these observations and of the results from other experiments as well as many subsequent corroborative measurements of comet Halley and of other comets are reviewed. Cometary nuclei are relative…
Overview of the soho mission
Bonnet, R. M.; Felici, F.
The SOHO spacecraft was launched on 2 December 1995, some 8 years after it started to be developed by European industry. Since 14 February 1996, SOHO is in a halo orbit around the Lagrangian point L1. It is continuously in view of the Sun, allowing uninterrupted sequences of observations of our star, a first in the development of solar physics. It…
Acceleration and modulation of energetic particles in the 3-D heliosphere by corotating interaction regions
Simnett, G. M.; Roelef, E. C.
The passage of the Ulysses spacecraft over the poles of the Sun in 1994/1996 has given us a unique insight into the physics of the third dimension of the heliosphere. During the 30-month transit from Jupiter to the south polar pass, the low-latitude heliosphere was dominated by a high speed solar wind stream which produced a corotating interaction…