skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Energy Distribution of Pickup Ions at the Solar Wind Termination Shock

Abstract

In-situ measurements taken by the Voyager 2 spacecraft suggest that the solar wind termination shock is significantly affected by the presence of pickup ions that are produced in the inner heliosphere due to charge exchange between interstellar neutrals and the solar wind ions. We use a fully kinetic particle-in-cell method to self-consistently simulate the shock with all physical properties available from Voyager 2. We have performed a set of simulations with varying velocity distribution functions for the pickup ions, since it was not determined by Voyager's measurements. We show that the measurements suggest that the pickup ions upstream of the shock are more energetic than generally believed. If their velocity distribution function assumes a filled-shell shape in the wind frame, the maximum cutoff speed for the pickup ions should be $≳$650 km s -1 in order to reproduce the measurements, which is almost twice the local wind speed. We suggest that pickup ions upstream of the shock are energized by adiabatic compression of the solar wind plasma as well as due to an enhanced level of turbulence in a broad foreshock region.

Authors:
ORCiD logo [1]; ORCiD logo [1];  [1]
  1. Princeton Univ., NJ (United States). Dept. of Astrophysical Sciences
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
Sponsoring Org.:
USDOE
OSTI Identifier:
1544059
Resource Type:
Journal Article
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Volume: 860; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Astronomy & Astrophysics

Citation Formats

Kumar, Rahul, Zirnstein, Eric J., and Spitkovsky, Anatoly. Energy Distribution of Pickup Ions at the Solar Wind Termination Shock. United States: N. p., 2018. Web. doi:10.3847/1538-4357/aabf96.
Kumar, Rahul, Zirnstein, Eric J., & Spitkovsky, Anatoly. Energy Distribution of Pickup Ions at the Solar Wind Termination Shock. United States. doi:10.3847/1538-4357/aabf96.
Kumar, Rahul, Zirnstein, Eric J., and Spitkovsky, Anatoly. Wed . "Energy Distribution of Pickup Ions at the Solar Wind Termination Shock". United States. doi:10.3847/1538-4357/aabf96.
@article{osti_1544059,
title = {Energy Distribution of Pickup Ions at the Solar Wind Termination Shock},
author = {Kumar, Rahul and Zirnstein, Eric J. and Spitkovsky, Anatoly},
abstractNote = {In-situ measurements taken by the Voyager 2 spacecraft suggest that the solar wind termination shock is significantly affected by the presence of pickup ions that are produced in the inner heliosphere due to charge exchange between interstellar neutrals and the solar wind ions. We use a fully kinetic particle-in-cell method to self-consistently simulate the shock with all physical properties available from Voyager 2. We have performed a set of simulations with varying velocity distribution functions for the pickup ions, since it was not determined by Voyager's measurements. We show that the measurements suggest that the pickup ions upstream of the shock are more energetic than generally believed. If their velocity distribution function assumes a filled-shell shape in the wind frame, the maximum cutoff speed for the pickup ions should be $≳$650 km s-1 in order to reproduce the measurements, which is almost twice the local wind speed. We suggest that pickup ions upstream of the shock are energized by adiabatic compression of the solar wind plasma as well as due to an enhanced level of turbulence in a broad foreshock region.},
doi = {10.3847/1538-4357/aabf96},
journal = {The Astrophysical Journal (Online)},
issn = {1538-4357},
number = 2,
volume = 860,
place = {United States},
year = {2018},
month = {6}
}

Works referenced in this record:

Preferential Heating and Acceleration of Heavy Ions in Impulsive Solar Flares
journal, February 2017


Hybrid simulations of the effects of interstellar pickup hydrogen on the solar wind termination shock
journal, January 1993

  • Liewer, P. C.; Goldstein, B. E.; Omidi, N.
  • Journal of Geophysical Research, Vol. 98, Issue A9
  • DOI: 10.1029/93JA01172

Magnetic fields at the solar wind termination shock
journal, July 2008

  • Burlaga, L. F.; Ness, N. F.; Acuña, M. H.
  • Nature, Vol. 454, Issue 7200
  • DOI: 10.1038/nature07029

Interstellar pickup ions and quasi-perpendicular shocks: Implications for the termination shock and interplanetary shocks
journal, January 1996

  • Zank, G. P.; Pauls, H. L.; Cairns, I. H.
  • Journal of Geophysical Research: Space Physics, Vol. 101, Issue A1
  • DOI: 10.1029/95JA02860

Pickup ion energization by shock surfing
journal, March 1996

  • Lee, Martin A.; Shapiro, Vitali D.; Sagdeev, Roald Z.
  • Journal of Geophysical Research: Space Physics, Vol. 101, Issue A3
  • DOI: 10.1029/95JA03570

Reforming perpendicular shocks in the presence of pickup protons: initial ion acceleration
journal, January 2005


Electron Heating in a Relativistic, Weibel-Unstable Plasma
journal, June 2015


Microstructure of the Heliospheric Termination Shock: Implications for Energetic Neutral atom Observations
journal, December 2009


Interstellar Pickup ion Acceleration in the Turbulent Magnetic Field at the Solar wind Termination Shock Using a Focused Transport Approach
journal, July 2016


The role pickup ions play in the termination shock: THE ROLE PUI PLAY IN THE TS
journal, June 2013

  • Ariad, D.; Gedalin, M.
  • Journal of Geophysical Research: Space Physics, Vol. 118, Issue 6
  • DOI: 10.1002/jgra.50170

Voyager 1 in the Foreshock, Termination Shock, and Heliosheath
journal, September 2005


On the flux and the energy spectrum of interstellar ions in the solar system
journal, March 1976


A Focused Transport Approach to Pickup Ion Shock Acceleration: Implications for the Termination Shock
journal, June 2007

  • le Roux, J. A.; Webb, G. M.; Florinski, V.
  • The Astrophysical Journal, Vol. 662, Issue 1
  • DOI: 10.1086/517601

Simulations of pickup ion mediated quasi-perpendicular shocks: Implications for the heliospheric termination shock
journal, April 2014

  • Matsukiyo, Shuichi; Scholer, Manfred
  • Journal of Geophysical Research: Space Physics, Vol. 119, Issue 4
  • DOI: 10.1002/2013JA019654

Hybrid simulations of the termination shock: Suprathermal ion velocity distributions in the heliosheath: ION DISTRIBUTIONS IN HELIOSHEATH
journal, November 2010

  • Wu, Pin; Liu, Kaijun; Winske, Dan
  • Journal of Geophysical Research: Space Physics, Vol. 115, Issue A11
  • DOI: 10.1029/2010JA015384

PICKUP ION DYNAMICS AT THE HELIOSPHERIC TERMINATION SHOCK OBSERVED BY VOYAGER 2
journal, May 2010


Contributions to the cross shock electric field at supercritical perpendicular shocks: impact of the pickup ions
journal, May 2012

  • Yang, Zhongwei; Han, Desheng; Yang, Huigen
  • Astrophysics and Space Science, Vol. 341, Issue 2
  • DOI: 10.1007/s10509-012-1111-9

Seven Years of Imaging the Global Heliosphere with IBEX
journal, April 2017

  • McComas, D. J.; Zirnstein, E. J.; Bzowski, M.
  • The Astrophysical Journal Supplement Series, Vol. 229, Issue 2
  • DOI: 10.3847/1538-4365/aa66d8

Structure of Energetic Particle Mediated Shocks Revisited
journal, May 2017


Reflection of pre-accelerated pick-up ions at the solar wind termination shock: The seed for anomalous cosmic rays
journal, October 1996


Constraining the pickup ion abundance and temperature through the multifluid reconstruction of the Voyager 2 termination shock crossing
journal, September 2015

  • Zieger, Bertalan; Opher, Merav; Tóth, Gábor
  • Journal of Geophysical Research: Space Physics, Vol. 120, Issue 9
  • DOI: 10.1002/2015JA021437

Interstellar Pickup Ion Observations to 38 au
journal, November 2017

  • McComas, D. J.; Zirnstein, E. J.; Bzowski, M.
  • The Astrophysical Journal Supplement Series, Vol. 233, Issue 1
  • DOI: 10.3847/1538-4365/aa91d2

IBEX—Interstellar Boundary Explorer
journal, April 2009


Pickup Ion Effect of the Solar Wind Interaction with the Local Interstellar Medium
journal, November 2016


The Solar Wind Around Pluto (SWAP) Instrument Aboard New Horizons
journal, August 2007


Phasespace transport of a quasi-neutral multi-fluid plasma over the solar wind MHD termination shock
journal, June 2012


Cool heliosheath plasma and deceleration of the upstream solar wind at the termination shock
journal, July 2008

  • Richardson, John D.; Kasper, Justin C.; Wang, Chi
  • Nature, Vol. 454, Issue 7200
  • DOI: 10.1038/nature07024

Structure of the Heliotail from Interstellar Boundary Explorer Observations: Implications for the 11-year Solar Cycle and Pickup Ions in the Heliosheath
journal, February 2017

  • Zirnstein, E. J.; Heerikhuisen, J.; Zank, G. P.
  • The Astrophysical Journal, Vol. 836, Issue 2
  • DOI: 10.3847/1538-4357/aa5cb2

Energy dissipation and ion heating at the heliospheric termination shock: TERMINATION SHOCK ENERGY DISSIPATION
journal, August 2009

  • Wu, P.; Winske, D.; Gary, S. P.
  • Journal of Geophysical Research: Space Physics, Vol. 114, Issue A8
  • DOI: 10.1029/2009JA014240

Perpendicular Shock Reformation and Ion Acceleration
journal, November 2005