Origin, Injection, and Acceleration of CIR Particles: Observations Report of Working Group 6

This report emphasizes new observational aspects of CIR ions revealed by advanced instruments launched on the Ulysses, WIND, SOHO, and ACE spacecraft, and by the unique vantage point of Ulysses which carried out the first survey of Corotating Interaction Region (CIR) properties over a very wide range of heliolatitudes. With this more complete observational picture established, this review is the basis to consider the status of theoretical models on origin, injection, and acceleration of CIR particles reported by Scholer, Mann et al. (1999) in this volume. This revised version was published online in August 2006 with corrections to the Cover Date.     

The Transition Between Fast and Slow Solar Wind from Composition Data

The transition between coronal hole associated fast solar wind and slow solar wind is studied using data from the high resolution mass spectrometer SWICS on ACE. We discuss the data in the framework of a recent theory about the global heliospheric magnetic field and conclude that the data are consistent with magnetic connections between field-lines in the fast and in the slow wind. This revised version was published online in June 2006 with corrections to the Cover Date.     

The Stratospheric and Mesospheric NOy in the 2002–2004 Polar Winters as measured by MIPAS/ENVISAT

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board ENVISAT, provided global (pole-to-pole, the polar night winter regions) measurements of nearly all constituents of the NO_y family (including NO, NO₂, HNO₃ and H₂O₅) from July 2002 to the end of March 2004 from the upper stratosphere up to the middle mesosphere. The inter-annual variability of the NO₂ and HNO₃ abundances in the Arctic and Antarctic winters from September 2002 through March 2004 was enormous with tremendous hemispheric asymmetry and extraordinary values in two winters. The origin of these variations and of the extreme measured values has been analyzed on the basis of the changing atmospheric dynamics (using the CH₄ tracer) and solar activity, including the extraordinary solar protons events of Oct–Nov 2003.     

Past and future of radio occultation studies of planetary atmospheres

Measurements of radio waves that have propagated through planetary atmospheres have provided exploratory results on atmospheric constituents, structure, dynamics, and ionization for Venus, Mars, Titan, Jupiter, Saturn, and Uranus. Highlights of past results are reviewed in order to define and illustrate the potential of occultation and related radio studies in future planetary missions.     

The Astrophysics of Galactic Cosmic Rays

Observations of cosmic rays and their related radio to gamma-ray signatures are surveyed and discussed critically, and compared to theoretical models of the cosmic-ray origin and propagation. The analogous heliospheric processes are included as a well-studied case of the principal physical processes of energetic particle acceleration and propagation. Reinforcements, or conflicts, in the interpretations of cosmic-ray spectral and compositional characteristics arise when cosmic-ray source and propagation models are confronted with astronomical information about the Galaxy as a whole and from potential source sites, i.e., supernova remnants or regions with high massive-star density. This volume represents the outcome of two workshops held at ISSI. In this chapter we summarize the introductory papers presented below, and include insights from the workshop discussions.     

Composition and structure of the atmosphere of Venus

Although in recent years much has been learned about the atmospheric composition and structure of Venus, there are many key questions which remain unanswered. The Pioneer Venus set of experiments is designed to provide information both individually and collectively to help understand and explain first of all the present state of the atmosphere (the composition and distribution in both the lower and upper parts, the state property profiles, the cloud compositions, the role of phase in the thermal structure, the planet's surface and interior composition, the high surface temperature, the stability of CO₂, the ionosphere — its chemistry and thermal structure, the existence of superrotation, the response of the upper atmosphere to changes in solar EUV and the solar wind) and secondly the origin and evolution of the atmosphere. This paper discusses these questions and the degree to which the Pioneer Venus instruments will respond to them.