Voyager 1 Near the heliopause
- Univ. of Alabama in Huntsville, AL (United States). Center for Space Physics and Aeronomic Research (CSPAR)
- Univ. of Alabama in Huntsville, AL (United States). Dept. of Space Sciences
Recent observations from the Voyager 1 spacecraft show that it is sampling the local interstellar medium (LISM). This is quite surprising because no realistic, steady-state model of the solar wind (SW) interaction with the LISM gives an inner heliosheath width as narrow as ~30 AU. This includes models that assume a strong redistribution of the ion energy to the tails in the pickup ion distribution function. We show that the heliopause (HP), which separates the SW from the LISM, is not a smooth tangential discontinuity, but rather a surface subject to Rayleigh-Taylor-type instabilities which can result in LISM material penetration deep inside the SW. We also show that the HP flanks are always subject to a Kelvin-Helmholtz instability. The instabilities are considerably suppressed near the HP nose by the heliospheric magnetic field in steady-state models, but reveal themselves in the presence of solar cycle effects. Here we argue that Voyager 1 may be in one such instability region and is therefore observing plasma densities much higher than those in the pristine SW. Lastly, these results may explain the early penetration of Voyager 1 into the LISM. They also show that there is a possibility that the spacecraft may start sampling the SW again before it finally leaves the heliosphere.
- Research Organization:
- Univ. of Alabama, Huntsville, AL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Grant/Contract Number:
- SC0008334; NNX10AE46G; NNX10AC17G; NNX12AB30G; OCI-1144120
- OSTI ID:
- 1326044
- Journal Information:
- The Astrophysical Journal. Letters, Vol. 783, Issue 1; ISSN 2041-8205
- Publisher:
- Institute of Physics (IOP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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