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Modulation of Cosmic Rays in the Heliosphere From Solar Minimum to Maximum: a Theoretical Perspective
Ferreira, S. E. S.; Potgieter, M. S.; Burger, R. A.
The modulation of galactic cosmic rays in the heliosphere seems to be dominated by four major mechanisms: convection, diffusion, drifts (gradient, curvature and current sheet), and adiabatic energy losses. In this regard the global structure of the solar wind, the heliospheric magnetic field (HMF), the current sheet (HCS), and that of the heliosph…
Ulysses' Second Orbit: Remarkably Different Solar Wind
McComas, D. J.; Goldstein, R.; Gosling, J. T. +1 more
By the time of the 34th ESLAB symposium, dedicated to the memory of John Simpson, Ulysses had nearly reached its peak southerly latitude in its second polar orbit. The global solar wind structure observed thus far in Ulysses' second orbit is remarkably different from that observed over its first orbit. In particular, Ulysses observed highly irregu…
Heliospheric and Interstellar Phenomena Deduced From Pickup ion Observations
Gloeckler, George; Geiss, Johannes
Pickup ions, created by ionization of slow moving atoms and molecules well inside the heliosphere, provide us with a new tool to probe remote regions in and beyond the heliosphere and to study injection and acceleration processes in the solar wind. Comprehensive and continuous measurements of H, He, C, N, O, Ne and other pickup ions, especially wi…
Simultaneous Observations of Solar Energetic Particle Events by imp 8 and the Ulysses Cospin High Energy Telescope at High Solar Latitudes
McKibben, R. B.; Zhang, M.; Lopate, C.
With Ulysses approaching the south solar polar latitudes during a period of high solar activity, it is for the first time possible to study the distribution of solar energetic particles (SEPs) in solar latitude as well as in radius and longitude. From July 1997 to August 2000, Ulysses moved from near the solar equator at ∼5 AU to ∼67° S latitude a…
The Heliospheric Magnetic Field at Solar Maximum: Ulysses Observations
Balogh, André; Smith, Edward J.
At solar maximum, the large-scale structure of the heliospheric magnetic field (HMF) reflects the complexity of the Sun's coronal magnetic fields. The corona is characterised by mostly closed magnetic structures and short-lived, small coronal holes. The axis of the Sun's dipole field is close to the solar equator; there are also important contribu…
Radio Frequency Fluctuation Spectra During the Solar Conjunctions of the Ulysses and Galileo Spacecraft
Plettemeier, D.; Bird, M. K.; Wohlmuth, R. +5 more
Temporal power spectra have been computed from recordings of the downlink frequency fluctuations of the Galileo and Ulysses radio signals during their solar conjunctions. Both the equatorial streamer belt and the polar coronal holes were investigated over a range of ray path solar offset distances from 4 to 80 R⊙. By combining gapless d…
The 3-D Heliosphere from the Ulysses and ACE Solar Wind Ion Composition Experiments
Geiss, J.; Schwadron, N. A.; Zurbuchen, T. H. +3 more
The source region of solar wind plasma is observed to be directly reflected in the compositional pattern of both elemental and charge state compositions. Slow solar wind associated with streamers shows higher freeze-in temperatures and larger FIP enhancements than coronal hole associated wind. Also, the variability of virtually all compositional p…
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…