Search Publications
Coordinated interhemispheric SuperDARN radar observations of the ionospheric response to flux transfer events observed by the Cluster spacecraft at the high-latitude magnetopause
Balogh, A.; Davies, J. A.; Wild, J. A. +11 more
At 10:00 UT on 14 February 2001, the quartet of ESA Cluster spacecraft were approaching the Northern Hemisphere high-latitude magnetopause in the post-noon sector on an outbound trajectory. At this time, the interplanetary magnetic field incident upon the dayside magnetopause was oriented southward and duskward (BZ negative, BY positive), having t…
Imprints from the solar cycle on the helium atom and helium pickup ion distributions
Fahr, H. J.; Bzowski, M.; Rucinski, D.
Neutral interstellar helium atoms penetrate into the solar system almost unaffected by gas-plasma interactions in the heliospheric interface region, and thus can be considered as carriers of original information on the basic parameters (like density, temperature, bulk velocity) of the Very Local Interstellar Medium (VLISM). Such information can no…
Delay in solar energetic particle onsets at high heliographic latitudes
Balogh, A.; Krucker, S.; Dalla, S. +9 more
Ulysses observations have shown that solar energetic particles (SEPs) can easily reach high heliographic latitudes. To obtain information on the release and propagation of SEPs prior to their arrival at Ulysses, we analyse the onsets of nine large high-latitude particle events. We measure the onset times in several energy channels, and plot them v…
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…