Interstellar Neutral Gas Flow Measurements with the Interstellar Boundary Explorer (IBEX) - Implications on Interstellar Medium and Heliosphere Diagnostics
Abstract
The Interstellar Boundary Explorer (IBEX) observes the interstellar neutral gas flow tra-jectories at their perihelion in Earth's orbit every year from December through late March, when the Earth moves into the oncoming flow. Surprisingly, the initial quantita-tive analysis resulted in a somewhat different interstellar flow vector with noticeably lower speed than obtained previously. In comparison with astronomical observations of the flow vectors of neighboring interstellar clouds, this result locates the solar system within the Local Interstellar Cloud (LIC), contrary to the previous determination, which indicated values between the LIC and the G-Cloud. This year, the fifth season is being accumulated, providing a database over increasing solar activity and with varying view-ing strategies. These recurring observations of the interstellar flow pattern and its spatial distribution allow us to consolidate the derived physical conditions of the surrounding interstellar medium. We can also track variations in the flow at 1 AU that may arise from solar cycle related changes in ionization and radiation pressure for H and explore any other variations of the neutral gas flow. Based on the angular distributions in latitude and longitude, the neutral flow observations also indicate the presence of a secondary compo-nent for most of the species, which most probably stems from charge exchange with ions in the outer heliosheath. We will review our observations and discuss implications for the LIC and its interaction with the heliosphere in the light of a growing data set and improv-ing analysis techniques.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2013
- Bibcode:
- 2013AGUSMSH54B..06M
- Keywords:
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- 2151 INTERPLANETARY PHYSICS / Neutral particles;
- 2126 INTERPLANETARY PHYSICS / Heliosphere/interstellar medium interactions;
- 2144 INTERPLANETARY PHYSICS / Interstellar gas