Search Publications
CIR Morphology, Turbulence, Discontinuities, and Energetic Particles
Tsurutani, B. T.; Lucek, E.; Crooker, N. U. +18 more
Corotating interaction regions (CIRs) in the middle heliosphere have distinct morphological features and associated patterns of turbulence and energetic particles. This report summarizes current understanding of those features and patterns, discusses how they can vary from case to case and with distance from the Sun and possible causes of those va…
The Solar Origin of Corotating Interaction Regions and Their Formation in the Inner Heliosphere
Bochsler, P.; Balogh, A.; Lucek, E. +20 more
Corotating Interaction Regions (CIRs) form as a consequence of the compression of the solar wind at the interface between fast speed streams and slow streams. Dynamic interaction of solar wind streams is a general feature of the heliospheric medium; when the sources of the solar wind streams are relatively stable, the interaction regions form a pa…
Solar Origin and Interplanetary Evolution of Stream Interfaces
Forsyth, R. J.; Marsch, E.
In a Corotating Interaction Region (CIR) the stream interface is identified as a relatively sharp density drop, temperature rise, and flow shear in the solar wind, and is now generally believed to mark the boundary between solar wind which was originally slow when it left the Sun and solar wind which was originally fast. This paper summarises some…
Solar Wind Models from the Sun to 1 AU: Constraints by in Situ and Remote Sensing Measurements
Marsch, E.
There are three major types of solar wind: The steady fast wind originating on open magnetic field lines in coronal holes, the unsteady slow wind coming probably from the temporarily open streamer belt and the transient wind in the form of large coronal mass ejections. The majority of the models is concerned with the fast wind, which is, at least …
Composition Variations in the Solar Corona and Solar Wind
Raymond, J. C.
Order of magnitude variations in relative elemental abundances are observed in the solar corona and solar wind. The instruments aboard SOHO make it possible to explore these variations in detail to determine whether they arise near the solar surface or higher in the corona. A substantial enhancement of low First Ionization Potential (FIP) elements…
Origin, Injection, and Acceleration of CIR Particles: Observations Report of Working Group 6
Fränz, M.; Simnett, G. M.; Klecker, B. +18 more
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 obse…
Swan Observations of the Solar Wind Latitude Distribution and its Evolution Since Launch
Bertaux, Jean-Loup; Lallement, Rosine; Schmidt, Walter +5 more
SWAN is the first space instrument dedicated to the monitoring of the latitude distribution of the solar wind by the Lyman alpha method. The distribution of interstellar H atoms in the solar system is determined by their destruction during ionization charge-exchange with solar wind protons. Maps of sky Ly-α emission have been recorded regularly si…
Modulation of Cosmic Rays and Anomalous Components by CIRs
Potgieter, M. S.; Richardson, I. G.; Heber, B. +6 more
CIRs produce clearly visible recurrent modulation in the intensity of cosmic rays and anomalous components, but are not principally responsible for determining the overall global level of modulation. However, the localized variations imposed by CIRs in the parameters for propagation of energetic particles through the solar wind provide useful diag…
EUV Observations Above Polar Coronal Holes
Del Zanna, G.; Fludra, A.; Bromage, B. J. I.
We derive electron temperature and density as a function of height up to 0.2 R⊙ above the limb in polar coronal holes, using five EUV data sets recorded by the SOHO Coronal Diagnostic Spectrometer between July 1997 and February 1998. Radial T and N distributions, averaged in a 2° to 10° range of position angles, are the same above the N…
Search for Signatures of a Coronal Hole in Transition Region Lines Near Disk Center
Bocchialini, K.; Wilhelm, K.; Lemaire, P. +2 more
The analysis of data taken by SUMER near disk center, where a small coronal hole is observed in EIT images, is performed. From the measurements of Doppler non-thermal velocities and intensities, we search for the diagnostics and the signature of small scale structures in the coronal hole using transition region lines. Transition region lines in th…