Search Publications
Origin of the Solar Wind: Theory
Schwadron, N. A.; Fisk, L. A.
A theory is presented for the origin of the solar wind, which is based on the behavior of the magnetic field of the Sun. The magnetic field of the Sun can be considered as having two distinct components: Open magnetic flux in which the field lines remain attached to the Sun and are dragged outward into the heliosphere with the solar wind. Closed m…
CME-Driven Solar Wind Disturbances at High Heliographic Latitudes
Forsyth, R. J.; Gosling, J. T.
We have identified 20 coronal mass ejections, or CMEs, in the solar wind in the Ulysses data obtained between S30° and S75° during the second polar orbit. Unlike CME-driven disturbances observed at high latitudes during Ulysses' first polar orbit, these disturbances had plasma and magnetic field characteristics similar to those observed in the ecl…
Cosmic Ray Modulation over the Poles at Solar Maximum: Observations
Heber, B.; Marsden, R. G.
Our knowledge of how galactic and anomalous cosmic rays are modulated in the inner heliosphere has been dramatically enlarged as a result of measurements from several missions launched in the past ten years. Among them, Ulysses explored the polar regions of the inner heliosphere during the last solar minimum period and is now revisiting southern p…
Kilometric Type III Radio Bursts, Electron Beams, and Interplanetary Density Structures
Reiner, Michael
We briefly review kilometric type III radio bursts and what their physical characteristics reveal about the propagation and characteristics of suprathermal electron beams and about density structures in interplanetary medium.
Stream Interaction Regions at High Heliographic Latitudes During Ulysses12/22/2004 6:25PM Second Polar Orbit
McComas, D. J.; Forsyth, R. J.; Gosling, J. T. +1 more
Ulysses observed well-defined stream interaction regions, SIRs, associated with solar wind stream structure up to a latitude of S65° and shocks to at least a latitude of S71° during the second polar orbit. These SIRs and shocks produced a substantial heliospheric processing of the solar wind. Only a subset of the SIRs recurred on successive solar …
Cosmic-ray Composition as Observed by Ulysses
Connell, James J.
The cosmic ray isotopic composition measurements from the High Energy Telescope (HET) on the Ulysses spacecraft are reviewed. The source isotopic composition of key elements is found to be surprisingly like the Solar system abundances with the notable exception of ^22Ne. The average density of interstellar material cosmic rays traverse is found to…
Time-Dependent 2d Model Compared with Observations During the 1974 Mini Cycle
Wibberenz, G.; Ferreira, S. E. S.; Potgieter, M. S. +1 more
The 1974 mini-cycle is a medium term cosmic ray modulation event with about one year duration. It occurred in an A>0 epoch of solar magnetic polarity during conditions of low activity, but with an increase in the latitudinal extent of the heliospheric current sheet (tilt angle α) and the magnitude B of the heliospheric magnetic field. This cosm…
Fast Dust in the Heliosphere
Grün, E.; Landgraf, M.
The dynamics of dust particles in the solar system is dominated by solar gravity, by solar radiation pressure, or by electromagnetic interaction of charged dust grains with the interplanetary magnetic field. For micron-sized or bigger dust particles solar gravity leads to speeds of about 30 to 40 km s^-1 at the Earth's distance. Smaller particles …
Joint Ulysses and ACE observations of a magnetic cloud and the associated solar energetic particle event
Lario, D.; Forsyth, R. J.; Tappin, S. J. +3 more
On day 49 of 1999 a strong interplanetary shock was observed by the ACE spacecraft located at 1 AU from the Sun. This shock was followed 10 hours later by a magnetic cloud (MC). A large solar energetic particle (SEP) event was observed in association with the arrival of the shock and the MC at ACE. The Ulysses spacecraft, located at 22° S heliolat…
Tracing the magnetic topology of coronal mass ejection events by Ulysses/HI-SCALE energetic particle observations in and out of the ecliptic
Pick, M.; Lanzerotti, L. J.; Sarris, E. T. +3 more
In January 2000, the Ulysses spacecraft observed an ICME event at 43° S heliographic latitude and ∼ 4.1 AU. We use electron (E e>38 keV) observations to trace the topology of the IMF embedded within the ICME. The still controversial issue of whether ICMEs have been detached from the solar corona or are still magnetically anchored to …