How does merging of CIRs affect shocks in the outer heliosphere?
Abstract
Observations of the solar wind in the outer heliosphere by Voyager 2 exhibit many examples of shocks. During the solar minimum in 1994-1997 near the distance 45 AU from the Sun Voyager 2 observed recurrent shocks and shock-like structures that were produced by corotating merged interaction regions. Measurements of the heliosheath plasma, emanated during the recent solar minima, do not show existence of shocks in the heliosheath. We explore an effect of merging of corotating interaction regions (CIRs) in the solar wind on the structure of CIR associated shocks. Using a 3D MHD model of the solar wind interaction with the local interstellar medium, we show that due to interaction of shocks and rarefaction waves in a process of merging of CIRs, the shocks strongly weaken in the outer heliosphere. Presented study suggests that merging process could be one of the explanations why Voyager 2 did not observe CIR associated shocks in the heliosheath while it showed several examples of shocks in the solar wind upstream the TS.
- Publication:
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Solar Heliospheric and INterplanetary Environment (SHINE 2012)
- Pub Date:
- June 2012
- Bibcode:
- 2012shin.confE..56P