Journal article
A Foreshock Model for Interstellar Shocks of Solar Origin: Voyager 1 and 2 Observations
The Astronomical journal, Vol.161(1), p.11
01/01/2021
DOI: 10.3847/1538-3881/abc337
Abstract
The Voyager 1 (V1) and Voyager 2 (V2) spacecraft were launched in 1977 on a mission to explore the outer planets and reach the heliopause, the boundary between the hot solar plasma and the relatively cool interstellar plasma. V1 reached the heliopause on 2012 August 25, at 121.6 au, and V2 reached the heliopause on 2018 November 5, at 119.0 au. One of their remarkable discoveries was the detection of shocks propagating into the interstellar plasma from energetic solar events. These shocks are typically preceded by electron plasma oscillations excited by electron beams streaming along interstellar magnetic field lines ahead of the shocks. The frequencies of the plasma oscillations have now provided radial electron density profiles in the outer heliosphere and in the interstellar medium to radial distances of more than 145 au. The oscillations are typically preceded by bursts of high-energy similar to 5-100 MeV electrons. These electron bursts are interpreted as being due to the reflection (and acceleration) of cosmic-ray electrons by the shock at the time the shock first contacts the magnetic field line that passes through the spacecraft. Relative timing between the cosmic rays reflected by the shock and the onset of the plasma oscillations allow us, for the first time, to estimate the energy, similar to 20-100 eV, of the electron beams responsible for the plasma oscillations. These observations are combined into a self-consistent model called the foreshock model that describes the interaction of shocks of solar origin with the interstellar plasma.
Details
- Title: Subtitle
- A Foreshock Model for Interstellar Shocks of Solar Origin: Voyager 1 and 2 Observations
- Creators
- D. A. Gurnett - University of IowaW. S. Kurth - University of IowaE. C. Stone - California Institute of TechnologyA. C. Cummings - California Institute of TechnologyB. Heikkila - Goddard Space Flight CenterN. Lal - Goddard Space Flight CenterS. M. Krimigis - Johns Hopkins University Applied Physics LaboratoryR. B. Decker - Johns Hopkins University Applied Physics LaboratoryN. F. Ness - University of DelawareL. F. Burlaga - Goddard Space Flight Center
- Resource Type
- Journal article
- Publication Details
- The Astronomical journal, Vol.161(1), p.11
- Publisher
- Iop Publishing Ltd
- DOI
- 10.3847/1538-3881/abc337
- ISSN
- 0004-6256
- eISSN
- 1538-3881
- Number of pages
- 11
- Grant note
- 80GSFC19C0012; 1622510; NNN12AA01C / NASA; National Aeronautics & Space Administration (NASA) NNN06AA01C / Voyager Interstellar Mission under NASA Jet Propulsion Laboratory
- Language
- English
- Date published
- 01/01/2021
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455542002771
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