Unsteady processes in the vicinity of the heliopause: Are we in the LISM yet?

Journal Article · Thu Jun 13 00:00:00 EDT 2013 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4811059· OSTI ID:1326064

Pogorelov, N. V. ^[1]; Borovikov, S. N. ^[2]; Burlaga, L. F. ^[3]; Ebert, R. W. ^[4]; Kryukov, I. A. ^[1]; Suess, S. T. ^[5]; Zank, G. P. ^[1]; Bedford, M. C. ^[1]

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1. Univ. of Alabama, Huntsville, AL (United States). Dept. of Physics and Center for Space Plasma and Aeronomic Research (CSPAR)
2. Univ. of Alabama, Huntsville, AL (United States). Center for Space Plasma and Aeronomic Research (CSPAR)
3. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States). Heliospheric Science Division
4. Southwest Research Inst. (SwRI), San Antonio, TX (United States)
5. National Space Science and Technology Center (NSSTC), Huntsville, AL (United States)

As the twin Voyager spacecraft approach the boundary of the heliosphere, they continue returning new and unexplained measurements of the solar wind (SW) protons, energetic particles, and magnetic field that often differ markedly between the two spacecraft. Our recent studies show that time-dependent effects play a crucial role in understanding and interpreting the observational data. Since the SW is unsteady on many different time scales, its interaction with the local interstellar medium (LISM) should reflect the solar rotation and cycle, as well as merged interplanetary disturbances. Even a simplified solar cycle model allowed us to predict in 2009 the possibility of a negative radial velocity component in the SWas the heliopause is approached. Further analysis shows a nearly vanishing latitudinal velocity component, while the longitudinal component becomes comparable substantial. Here we discuss the change of the magnetic field and plasma properties across the heliopause, which is important for the identification of its spacecraft crossing. In conclusion, we discuss the effects of heliopause instabilities and corotating interaction regions, and demonstrate that Voyagers are unlikely to see a sharp boundary between the SW and the LISM, but rather a mixing layer of varying width.

• Research Organization: Univ. of Alabama, Huntsville, AL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Fusion Energy Sciences (FES); National Aeronautics and Space Administration (NASA)
• Grant/Contract Number: SC0008334; NNX08AE41G; NNX08AG62G; NNX08AJ21G; NNX09AB24G, NNX09AG29G, NNX09AP74A; NNX09AW44G; NNX09AG63G; NNX10AE46G; NNX12AB30G
• OSTI ID: 1326064
• Journal Information: AIP Conference Proceedings, Vol. 1539; Conference: SOLAR WIND 13: Proceedings of the Thirteenth International Solar Wind Conference, Big Island, Hawaii (United States), 17-22 Jun 2012; ISSN 0094-243X
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
interplanetary and interstellar magnetic fields
heliopause
solar wind termination
solar cycle variations
multi-fluid plasma
magnetohydrodynamics