Search Publications
Charge-sign dependent modulation in the heliosphere over a 22-year cycle
Fichtner, H.; Ferreira, S. E. S.; Potgieter, M. S. +1 more
A time-dependent model based on a numerical solution of Parker's transport equation is used to model the modulation of cosmic ray protons, electrons and helium for full 11-year and 22-year modulation cycles using a compound approach. This approach incorporates the concept of propagating diffusion barriers based on global increases in the heliosphe…
On the solar origin of interplanetary disturbances observed in the vicinity of the Earth
Schwenn, R.; Pick, M.; Vilmer, N. +2 more
The solar origin of 40 interplanetary disturbances observed in the vicinity of the Earth between January 1997 and June 1998 is investigated in this paper. Analysis starts with the establishment of a list of Interplanetary Mass Ejections or ICMEs (magnetic clouds, flux ropes and ejecta) and of Interplanetary Shocks measured at WIND for the period f…
Cusp structures: combining multi-spacecraft observations with ground-based observations
Escoubet, C. P.; Dandouras, I.; Klecker, B. +16 more
Recent simultaneous observations of cusp structures with Polar, FAST and Interball revealed remarkably similar features at spacecraft crossing the cusp. Such stable cusp structures could be observed up to several hours only during stable solar wind conditions. Their similarities led to the conclusion that for such conditions large-scale cusp struc…
How did the solar wind structure change around the solar maximum? From interplanetary scintillation observation
McComas, D. J.; Elliott, H. A.; Tokumaru, M. +5 more
Observations from the second Ulysses fast latitude scan show that the global structure of solar wind near solar maximum is much more complex than at solar minimum. Soon after solar maximum, Ulysses observed a polar coronal hole (high speed) plasma with magnetic polarity of the new solar cycle in the Northern Hemisphere. We analyze the solar wind s…
Dynamical evolution of the inner heliosphere approaching solar activity maximum: interpreting Ulysses observations using a global MHD model
Riley, P.; Linker, J. A.; Mikic, Z.
In this study we describe a series of MHD simulations covering the time period from 12 January 1999 to 19 September 2001 (Carrington Rotation 1945 to 1980). This interval coincided with: (1) the Sun's approach toward solar maximum; and (2) Ulysses' second descent to the southern polar regions, rapid latitude scan, and arrival into the northern pol…
Polar, Cluster and SuperDARN evidence for high-latitude merging during southward IMF: temporal/spatial evolution
Wild, J. A.; Lester, M.; Dunlop, M. +5 more
Magnetic merging on the dayside magnetopause often occurs at high latitudes. Polar measured fluxes of accelerated ions and wave Poynting vectors while skimming the subsolar magnetopause. The measurements indicate that their source was located to the north of the spacecraft, well removed from expected component merging sites. This represents the fi…
Magnetic topology of coronal mass ejection events out of the ecliptic: Ulysses/HI-SCALE energetic particle observations
Sarris, E. T.; Malandraki, O. E.; Tsiropoula, G.
Solar energetic particle fluxes (Ee > 38 keV) observed by the ULYSSES/HI-SCALE experiment are utilized as diagnostic tracers of the large-scale structure and topology of the Interplanetary Magnetic Field (IMF) embedded within two well-identified Interplanetary Coronal Mass Ejections (ICMEs) detected at 56° and 62° south heliolatitudes by ULYSSE…
The global heliospheric magnetic field polarity distribution as seen at Ulysses
Balogh, A.; Jones, G. H.
The Ulysses spacecraft is in a near-polar solar orbit with a period of 6.2 years. The heliospheric magnetic field polarity detected by Ulysses from its 1992 Jupiter encounter to the current time is presented, following ballistic mapping of the polarity information to the solar wind source surface, at approximately 2.5 solar radii. The spacecraft's…
Consequences of the Solar System passage through dense interstellar clouds
Fahr, H. J.; Yeghikyan, A. G.
Several consequences of the passage of the solar system through dense interstellar molecular clouds are discussed. These clouds, dense (more than 100 cm-3), cold (10-50 K) and extended (larger than 1 pc), are characterized by a gas-to-dust mass ratio of about 100, by a specific power grain size spectrum (grain radii usually cover the range 0.001-3…
Latitudinal and radial variation of >2 GeV/n protons and alpha-particles at solar maximum: Ulysses COSPIN/KET and neutron monitor network observations
Kunow, H.; Heber, B.; Müller-Mellin, R. +4 more
Ulysses, launched in October 1990, began its second out-of-ecliptic orbit in September 1997. In 2000/2001 the spacecraft passed from the south to the north polar regions of the Sun in the inner heliosphere. In contrast to the first rapid pole to pole passage in 1994/1995 close to solar minimum, Ulysses experiences now solar maximum conditions. The…