Title: Voyager 1 Near the heliopause

Abstract

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 samplingmore » the SW again before it finally leaves the heliosphere.« less

Authors:

Borovikov, S. N. ^[1]; Pogorelov, N. V. ^[2]

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+ Show Author Affiliations

1. Univ. of Alabama in Huntsville, AL (United States). Center for Space Physics and Aeronomic Research (CSPAR)
2. Univ. of Alabama in Huntsville, AL (United States). Dept. of Space Sciences

Publication Date:

Tue Feb 18 00:00:00 EST 2014

Research Org.:

Univ. of Alabama, Huntsville, AL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Fusion Energy Sciences (FES)

OSTI Identifier:

1326044

Grant/Contract Number:  

SC0008334; NNX10AE46G; NNX10AC17G; NNX12AB30G; OCI-1144120

Resource Type:

Accepted Manuscript

Journal Name:

The Astrophysical Journal. Letters

Additional Journal Information:

Journal Volume: 783; Journal Issue: 1; Journal ID: ISSN 2041-8205

Publisher:

Institute of Physics (IOP)

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; ISM: kinematics and dynamics; ISM: magnetic fields; solar wind; Sun: heliosphere