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The new ESA meteoroid model
Dikarev, V.; Grün, E.; Landgraf, M. +3 more
The orbital distributions of meteoroids in interplanetary space are revised in the ESA meteoroid model to account for recently obtained observational data and to comply with the constraints due to the orbital evolution under planetary gravity and Poynting-Robertson effects. Infrared observations of the zodiacal cloud by the COBE DIRBE instrument, …
The heliospheric modulation of 3 10 MeV electrons: Modeling of changes in the solar wind speed in relation to perpendicular polar diffusion
Fichtner, H.; Ferreira, S. E. S.; Potgieter, M. S. +3 more
The discrepancy between cosmic ray model predictions representing solar minimum conditions in the heliosphere and the 3-10 MeV post-1998 electrons observations by the Kiel Electron Telescope (KET) onboard Ulysses suggests the need for consistent changes in model parameters with increasing solar activity. In order to reduce this discrepancy, an eff…
Cosmic-ray diffusion in the inner heliosphere
McKibben, R. B.
For about the last 40 years, we have been trying to understand the propagation of cosmic rays and other energetic charged particles through the interplanetary medium. Identification of the basic processes affecting the propagation, namely diffusion, convection by the solar wind, adiabatic deceleration, and gradient and curvature drifts, was attain…
The transport of galactic and jovian cosmic ray electrons in the heliosphere
Ferreira, S. E. S.
An overview is given on what we know about the cosmic ray diffusion process from the modelling of low-energy (MeV) electron transport in the heliosphere. For energies below ∼300 MeV, these electrons give a direct indication of the average mean free paths because they do not experience large adiabatic energy changes and their modulation is largely …
In situ observations of magnetic field fluctuations
Balogh, André; Erdős, Géza
It is well known that the irregularities of the magnetic field are intimately related to the motion of charged particles. Although transport theories need the spatial and time variations of the magnetic field as input, in situ observations are very limited. Ulysses observations have provided a major step forward by entering the unexplored high lat…
Properties of solar wind turbulence near the Sun as deduced from coronal radio sounding experiments
Plettemeier, D.; Bird, M. K.; Efimov, A. I. +2 more
The characteristics of plasma turbulence in the inner solar wind, as deduced from radio frequency fluctuation measurements recorded during solar conjunction, are reviewed. Special emphasis is placed on results from the radio occultation experiments performed with the Galileo and Ulysses spacecraft in the interval 1991-2000. Estimates of the power …
On the determination of energy spectra of MeV electrons by the Ulysses COSPIN/KET
Fichtner, H.; Ferreira, S. E. S.; Heber, B. +1 more
The Ulysses mission has provided a wealth of data, particularly regarding the transport of low-energy cosmic ray electrons. These data have been used to derive significant constraints for the anisotropic spatial diffusion of these particles. Detailed model simulations allowed, in addition, to determine the relative contributions of galactic and Jo…
Comparison of the effects of two models for perpendicular diffusion on cosmic-ray latitudinal gradients
Matthaeus, W. H.; Bieber, J. W.; Burger, R. A. +2 more
We compare the effects of two different models for perpendicular diffusion on the latitudinal gradients of galactic cosmic ray protons during solar minimum conditions. These two models correspond to the newly developed non-linear guiding center theory [Matthaeus, W.H., Qin, G., Bieber, J.W., Zank, G.P. Nonlinear collisionless perpendicular diffusi…
Model of the all-sky He II 30.4 nm solar flux
Auchère, F.; von Steiger, R.; Witte, M. +3 more
Because of the orbit characteristics of the vast majority of spacecraft, the solar flux has been generally measured at Earth or in the plane of the ecliptic. So far, most published studies did not consider the fact that the extreme ultraviolet (EUV) solar flux is largely anisotropic. Indeed, in the EUV, the distribution of very contrasted bright a…
Solar wind velocity measurements near the sun using Ulysses radio amplitude correlations at two frequencies
Plettemeier, D.; Bird, M. K.; Efimov, A. I. +4 more
Measurements of solar wind velocity have been derived from simultaneous coronal sounding observations of radio amplitude scintillations at both S-band and X-band during the solar conjunction of the Ulysses spacecraft in August 1991. The signal amplitude was recorded with an averaging time of 1 s. A cross-correlation analysis between S- and X-band …