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Studies of reconnection in the solar wind led by Gosling and collaborators have revealed surprising results that are posing serious challenges to current theoretical understanding of the reconnection process. These include presence of prolonged quasi-steady reconnection, low magnetic shear angles, and no substantial particle acceleration. Here we put forth the conjecture that many of the solar wind exhaust events may be fossil sites. We explore the viability of this possibility using full particle simulations. [ABSTRACT FROM AUTHOR]

We analyze measurements of the 0.5-1.0 MeV/nucleon H/He intensity ratio from the Ulysses spacecraft during its first (1992-1994) and second (1999-2000) ascents to southern high latitude regions of the heliosphere. These cover a broad range of heliocentric distances (from 5.2 to 2.0 AU) and out-of-ecliptic latitudes (from 18°S to 80°S). During Ulysses' first southern pass, the HI-SCALE instrument measured a series of enhanced particle fluxes associated with the passage of a recurrent corotating interaction region (CIR). Low values (∼6) of the H/He ratio were observed in these recurrent corotating events, with a clear minimum following the passage of the corotating reverse shock. When Ulysses reached high southern latitudes (>40°S), the H/He ratio always remained below ∼10 except during two transient solar events that brought the ratio to high (>20) values. Ulysses' second southern pass was characterized by a higher average value of the H/He ratio. No recurrent pattern was observed in the energetic ion intensity, which was dominated by the occurrence of transient events of solar origin. Numerous stream interaction regions (SIRs) were observed in the solar wind and magnetic field data, many of which were bounded by forward and reverse shock pairs. The arrival of those SIRs at Ulysses usually produced an energetic particle flux enhancement, but they were not always characterized by a decrease of the H/He ratio; on the contrary, many SIRs showed a higher H/He ratio than some transient events. Within a SIR, however, the H/He ratio usually increased around the forward shock and decreased towards the reverse shock. Throughout the second ascent to southern heliolatitudes, the H/He ratio seldom decreased below ∼10 even at high latitudes (>40°S). We interpret these higher values of the H/He ratio in terms of the increasing level of solar activity together with the poor definition and short life that corotating solar wind structures have under... [ABSTRACT FROM AUTHOR]

This paper provides a brief synthesis of certain aspects of the electric and magnetic field structure of a collisiontess shock in the solar wind and outlines how electron heating and acceleration at the shock is related to that structure. Emphasis is on measurements obtained in the vicinity of Earth's bow shock, although the results should have broad applicability to other shocks in the heliosphere. [ABSTRACT FROM AUTHOR]

The most dramatic changes in the solar corona occur during coronal mass ejections, or CMEs, during which solar material is propelled outward into the heliosphere from regions in the corona not previously participating in the solar wind expansion. These ejections often produce major solar wind disturbances, large geomagnetic storms, enhancements of moderate energy (MeV) particle fluxes and decreases in the galactic cosmic ray particle flux. This paper provides an overview of the CME phenomenon with emphasis on the CMEs themselves and how they evolve as they propagate out through the heliosphere. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]