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Title: Observations of the He{sup +} pickup ion torus velocity distribution function with SOHO/CELIAS/CTOF

Abstract

Interstellar PickUp Ions (PUIs) are created from neutrals coming from the interstellar medium that get ionized inside the heliosphere. Once ionized, the freshly created ions are injected into the magnetized solar wind plasma with a highly anisotropic torus-shaped Velocity Distribution Function (VDF). It has been commonly assumed that wave-particle interactions rapidly destroy this torus by isotropizing the distribution in one hemisphere of velocity space. However, recent observations of a He{sup +} torus distribution using PLASTIC on STEREO showed that the assumption of a rapid isotropization is oversimplified. The aim of this work is to complement these studies. Using He{sup +} data from the Charge Time-Of-Flight (CTOF) sensor of the Charge, ELement, and Isotope Analysis System (CELIAS) on-board the SOlar and Heliospheric Observatory (SOHO) and magnetic field data from the Magnetic Field Investigation (MFI) magnetometer of the WIND spacecraft, we derive the projected 1-D VDF of He{sup +} for different magnetic field configurations. Depending on the magnetic field direction, the initial torus VDF lies inside CTOF’s aperture or not. By comparing the VDFs derived under different magnetic field directions with each other we reveal an anisotropic signature of the He{sup +} VDF.

Authors:
; ; ;  [1];  [2];  [3]
  1. Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaät zu Kiel, Leibnizstrasse 11, 24118 Kiel (Germany)
  2. Physikalisches Institut, Universität Bern, Sidlerstrasse 5, 3012 Bern (Switzerland)
  3. Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching (Germany)
Publication Date:
OSTI Identifier:
22590914
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 1720; Journal Issue: 1; Conference: SOLAR WIND 14: 14. international solar wind conference, Weihai (China), 22-26 Jun 2015; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; APERTURES; ASTROPHYSICS; COMPARATIVE EVALUATIONS; DISTRIBUTION FUNCTIONS; HELIOSPHERE; HELIUM IONS; INTERPLANETARY MAGNETIC FIELDS; MAGNETIC FIELD CONFIGURATIONS; MAGNETOMETERS; PARTICLE INTERACTIONS; PLASMA; SENSORS; SOLAR WIND; SPACE VEHICLES; TIME-OF-FLIGHT METHOD; VELOCITY

Citation Formats

Taut, Andreas, Berger, Lars, Drews, Christian, Wimmer-Schweingruber, Robert F., Bochsler, Peter, and Klecker, Berndt. Observations of the He{sup +} pickup ion torus velocity distribution function with SOHO/CELIAS/CTOF. United States: N. p., 2016. Web. doi:10.1063/1.4943835.
Taut, Andreas, Berger, Lars, Drews, Christian, Wimmer-Schweingruber, Robert F., Bochsler, Peter, & Klecker, Berndt. Observations of the He{sup +} pickup ion torus velocity distribution function with SOHO/CELIAS/CTOF. United States. doi:10.1063/1.4943835.
Taut, Andreas, Berger, Lars, Drews, Christian, Wimmer-Schweingruber, Robert F., Bochsler, Peter, and Klecker, Berndt. Fri . "Observations of the He{sup +} pickup ion torus velocity distribution function with SOHO/CELIAS/CTOF". United States. doi:10.1063/1.4943835.
@article{osti_22590914,
title = {Observations of the He{sup +} pickup ion torus velocity distribution function with SOHO/CELIAS/CTOF},
author = {Taut, Andreas and Berger, Lars and Drews, Christian and Wimmer-Schweingruber, Robert F. and Bochsler, Peter and Klecker, Berndt},
abstractNote = {Interstellar PickUp Ions (PUIs) are created from neutrals coming from the interstellar medium that get ionized inside the heliosphere. Once ionized, the freshly created ions are injected into the magnetized solar wind plasma with a highly anisotropic torus-shaped Velocity Distribution Function (VDF). It has been commonly assumed that wave-particle interactions rapidly destroy this torus by isotropizing the distribution in one hemisphere of velocity space. However, recent observations of a He{sup +} torus distribution using PLASTIC on STEREO showed that the assumption of a rapid isotropization is oversimplified. The aim of this work is to complement these studies. Using He{sup +} data from the Charge Time-Of-Flight (CTOF) sensor of the Charge, ELement, and Isotope Analysis System (CELIAS) on-board the SOlar and Heliospheric Observatory (SOHO) and magnetic field data from the Magnetic Field Investigation (MFI) magnetometer of the WIND spacecraft, we derive the projected 1-D VDF of He{sup +} for different magnetic field configurations. Depending on the magnetic field direction, the initial torus VDF lies inside CTOF’s aperture or not. By comparing the VDFs derived under different magnetic field directions with each other we reveal an anisotropic signature of the He{sup +} VDF.},
doi = {10.1063/1.4943835},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 1720,
place = {United States},
year = {2016},
month = {3}
}