Search Publications
Formation and Evolution of Corotating Interaction Regions and their Three Dimensional Structure
Gosling, J. T.; Pizzo, V. J.
Corotating interaction regions are a consequence of spatial variability in the coronal expansion and solar rotation, which cause solar wind flows of different speeds to become radially aligned. Compressive interaction regions are produced where high-speed wind runs into slower plasma ahead. When the flow pattern emanating from the Sun is roughly t…
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…
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 …
CIR Associated Energetic Particles in the Inner and Middle Heliosphere
Mason, G. M.; Sanderson, T. R.
Energetic particles associated with Corotating Interaction Regions (CIRs) are observed throughout the inner and middle heliosphere, showing large positive (>100%/AU) radial intensity gradients. Their appearance at 1 AU is associated with the appearance of fast, recurrent solar wind streams. At several AU, CIR energetic particles are accelerated…
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…
Observation of Injection and Pre-Acceleration Processes in the Slow Solar Wind
Gloeckler, George
Knowledge of injection and pre-acceleration mechanisms of ions is of fundamental importance for understanding particle acceleration that takes place in various astrophysical settings. The heliosphere offers the best chance to study these poorly understood processes experimentally. We examine ion injection and pre-acceleration using measurements of…
Mechanisms for Latitudinal Transport of Energetic Particles in the Heliosphere
Fisk, L. A.; Jokipii, J. R.
Energetic particles in the heliosphere, from relatively low-energy particles which are accelerated in Corotating Interaction Regions (CIRs) to galactic cosmic rays, are observed to propagate relatively easily in heliographic latitude. Two mechanisms for this transport appear possible: cross-field diffusion, or, in a recent model for the heliospher…
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…
Coronal Hole Boundaries and their Interactions with Adjacent Regions
Schwadron, N. A.; Zurbuchen, T. H.; Fisk, L. A.
Coronal hole boundaries are the interfaces between regions where the coronal magnetic field contains a significant component which is open into the heliosphere and regions where the field is primarily closed. It is pointed out that there are constraints on the magnetic field which opens into the heliosphere that must be satisfied in the corona: it…