EDP Sciences
Free Access
Volume 404, Number 3, June IV 2003
Page(s) L47 - L50
Section Letters
DOI https://doi.org/10.1051/0004-6361:20030670

A&A 404, L47-L50 (2003)
DOI: 10.1051/0004-6361:20030670


Remote diagnostic of the solar-cycle-induced heliospheric interface variation using energetic neutral atoms

K. Scherer and H.-J. Fahr

Institut für Astrophysik und Extraterrestrische Forschung, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
(Received 19 March 2003 / Accepted 28 April 2003)

The region of perturbed plasma flows between the supersonic solar wind and the supersonic interstellar plasma is generally called the heliospheric interface. This extended plasma region at the boundary of the heliosphere, though theoretically thoroughly studied and revealed as strongly time-variable during the solar activity cycle, is up to the present not accessible by direct or remote observations. Here we emphasize the possibility to remotely investigate this time-variable region by imaging it through energetic neutral atoms. We calculate the time-dependent distribution function of keV-energetic neutral H-atoms originating as products of charge exchange reactions between H-atoms and protons in the interface region. By carrying out line-of sight integrations of time-variable spectral sources of energetic neutral H-atoms we estimate their fluxes for an earth-bound detector as function of time within the solar activity cycle. Our predictions can directly be taken as a basis for the interpretation of planned heliospheric ENA-measurements upcoming in the near future.

Key words: outer heliosphere -- solar cycle variation -- ENA flux

Offprint request: K. Scherer, kscherer@astro.uni-bonn.de

© ESO 2003