Mediation of the solar wind termination shock by non-thermal ions

Document Type

Article

Publication Date

7-3-2008

Abstract

Broad regions on both sides of the solar wind termination shock are populated by high intensities of non-thermal ions and electrons. The pre-shock particles in the solar wind have been measured by the spacecraft Voyager 1 (refs 1-5) and Voyager 2 (refs 3, 6). The post-shock particles in the heliosheath have also been measured by Voyager 1 (refs 3-5). It was not clear, however, what effect these particles might have on the physics of the shock transition until Voyager 2 crossed the shock on 31 August-1 September 2007 (refs 7-9). Unlike Voyager 1, Voyager 2 is making plasma measurements. Data from the plasma and magnetic field instruments on Voyager 2 indicate that non-thermal ion distributions probably have key roles in mediating dynamical processes at the termination shock and in the heliosheath. Here we report that intensities of low-energy ions measured by Voyager 2 produce non-thermal partial ion pressures in the heliosheath that are comparable to (or exceed) both the thermal plasma pressures and the scalar magnetic field pressures. We conclude that these ions are the >0.028 MeV portion of the non-thermal ion distribution that determines the termination shock structure and the acceleration of which extracts a large fraction of bulk-flow kinetic energy from the incident solar wind. ©2008 Macmillan Publishers Limited. All rights reserved.

Identifier

46449112392 (Scopus)

Publication Title

Nature

External Full Text Location

https://doi.org/10.1038/nature07030

e-ISSN

14764687

ISSN

00280836

First Page

67

Last Page

70

Issue

7200

Volume

454

Grant

NNX07AB02G

Fund Ref

National Aeronautics and Space Administration

This document is currently not available here.

Share

COinS