RADIAL VELOCITY ALONG THE VOYAGER 1 TRAJECTORY: THE EFFECT OF SOLAR CYCLE
- Physics Department, The University of Alabama in Huntsville, AL 35805 (United States)
- Center for Space Physics and Aeronomic Research, The University of Alabama in Huntsville, AL 35805 (United States)
- Geospace Physics Laboratory, Code 673, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States)
- Space Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States)
As Voyager 1 and Voyager 2 are approaching the heliopause (HP)-the boundary between the solar wind (SW) and the local interstellar medium (LISM)-we expect new, unknown features of the heliospheric interface to be revealed. A seeming puzzle reported recently by Krimigis et al. concerns the unusually low, even negative, radial velocity components derived from the energetic ion distribution. Steady-state plasma models of the inner heliosheath (IHS) show that the radial velocity should not be equal to zero even at the surface of the HP. Here we demonstrate that the velocity distributions observed by Voyager 1 are consistent with time-dependent simulations of the SW-LISM interaction. In this Letter, we analyze the results from a numerical model of the large-scale heliosphere that includes solar cycle effects. Our simulations show that prolonged periods of low to negative radial velocity can exist in the IHS at substantial distances from the HP. It is also shown that Voyager 1 was more likely to observe such regions than Voyager 2.
- OSTI ID:
- 22047869
- Journal Information:
- Astrophysical Journal Letters, Vol. 750, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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