Search Publications
Radial and latitudinal intensity gradients of galactic and anomalous cosmic rays in the outer heliosphere
McDonald, F. B.; Fujii, Z.
The basic one~@~Sdimensional transport model gives the equation, gr=CVSW/~Zrr where C is the Compton-Getting factor, VSW is the solar wind velocity and ~Zrr is thee radial diffusion coefficient. In the inner heliosphere near the ecliptic plane ~Zrr iss dominated by the parallel diffusion with transition to perpendicular diffusion at near 10 AU in …
Diffusive Particle Transport in Heliomagnetic Fields with Organized Latitudinal Components
Jokipii, J. R.; Kota, J.
We discuss the potential role the meridional component of the large-scale heliospheric magnetic field (HMF) might play in the transport of cosmic rays. The standard Archimedean spiral lines of the steady, large-scale HMF has no latitudinal component. Hence latitudinal transport of particles may occur only through particle drifts and cross-field di…
Compressive-Diffusive Acceleration of Energetic Charged Particles
Giacalone, J.; Jokipii, J. R.; Kota, J.
We discuss the phenomenon of the acceleration of charged particles in a compressing di~@usive medium and apply it to recent ACE observations in the interplanetary medium. It has been recognized that the phenomenon of di~@usive shock acceleration can readily be generalized to the case where the the shock isreplaced by a gradual change in the veloci…
Cosmic ray and solar particle composition measurements in the southern solar polar region
Sanderson, T. R.; Marsden, R. G.; Tranquille, C. +2 more
This analysis is based on energetic particle measurements covering the energy range 4-20 MeV/n recorded by the COSPIN/LET instrument on the Ulysses spacecraft. Around the end of the year 2000 the Ulysses spacecraft was above the southern polar region at less than 2.5 AU radial distance from the Sun. A preliminary analysis has shown that the abunda…
Latitudinal and radial variation of >2 GeV/n protons and alpha particles in the southern heliosphere at solar maximum: Ulysses cospinket and neutron monitor network observations
Kunow, H.; Wibberenz, G.; Heber, B. +7 more
Ulysses, launched in October 1990, began in its second out-of-ecliptic orbit in September 1997 and its second fast latitude scan in November 2000. In contrast to the first orbit with the Sun declining to low activity, we are now at solar maximum conditions. The Kiel Electron Telescope (KET) on-board Ulysses measures proton and alpha-particles in t…
The cosmic ray radial and latitudinal gradients in the heliosphere near solar minima
Zhang, M.; McDonald, F. B.
Based on existing measurements of galactic and anomalous cosmic ray gradients obtained by the heliopsheric network spacecraft in the last three solar minima, we found that there is an approximately linear relationship between the magnitudes of the radial gradient and latitudinal gradient. Cosmic rays of a particular species/energy that exhibit a l…
The Ulysses Fast Latitude Scan at Solar Maximum: COSPIN/LET energetic particle observations
Forsyth, R. J.; Sanderson, T. R.; Marsden, R. G. +3 more
Having completed the second survey of the southern polar regions of the heliosphere in late 2000, the Ulysses spacecraft is presently engaged in its second so-called Fast Latitude Scan (FSL). During this phase of the out-of-ecliptic orbit, the spacecraft makes a rapid transit from south to north, covering 160° in solar latitude in less than 320 da…
Time-dependent 3-D modelling of the heliospheric propagation of few-MeV electrons
Fichtner, H.; Ferreira, S. E. S.; Potgieter, M. S. +2 more
With a recently developed steady-state model of the propagation of Jovian and galactic electrons in the inner three-dimensional heliosphere we were able to demonstrate both the necessity and value of such modelling for (i) the determination of the diffusion tensor of energetic particles, (ii) an observational discrimination between Jovian and inte…
Intensities of galactic cosmic ray nuclei from the ecliptic to the south solar polar regions near solar maximum: observations from the ULYSSES COSPIN high energy telescope
Heber, B.; McKibben, R. B.; Zhang, M. +2 more
Ulysses reached its maximum south heliographic latitude of 80.2° S in late November 2000, near the maximum in the solar activity cycle and is now embarked on a fast latitude scan that will bring it to a perihelion at 1.34 AU near the solar equator by mid-May 2001. Throughout the period of increasing solar activity since Ulysses left the ecliptic i…
Ulysses High Energy Telescope Measurements of the Isotopic Abundances of Galactic Cosmic Rays for Elements between C and Fe with Estimates of the Source Composition
Connell, J. J.
We report new and revised high resolution measurements of the isotopic composition of Galactic cosmic rays in the Solar system using data from the High Energy Telescope (HET) on the Ulysses Spacecraft. These data have significantly improved statistics compared with our earlier measurements. Mass resolution varies from ~0.08 to ~0.31 u at observed …