STEREO Observations of Energetic, ~4- 20 keV Neutral Atoms from the Heliosheath

Details STEREO Observations of Energetic, ~4- 20 keV Neutral Atoms from the Heliosheath STEREO Observations of Energetic, ~4- 20 keV Neutral Atoms from the Heliosheath

May 2008

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agusmsh24a..05w&link_type=abstract

American Geophysical Union, Spring Meeting 2008, abstract #SH24A-05

Physics

2114 Energetic Particles (7514), 2126 Heliosphere/Interstellar Medium Interactions, 2144 Interstellar Gas, 2151 Neutral Particles (7837), 2152 Pickup Ions

Scientific paper

We report the first observations, by the two STEREO spacecraft at ~0.96 & ~1.1 AU, of ~4-20 keV ENAs produced by charge exchange of suprathermal ions with interstellar neutrals in the heliosheath. We find a wide (~60°), asymmetric double-peak ENA flow with the stronger peak at ~65° and the weaker peak at ~90°, straddling the interstellar gas flow direction (74°). Thus, these ENAs come from the nose of heliosphere. The observed ENA fluxes fit well to a double-power-law spectrum with a break at ~10-12 keV, but on average, the energy spectra of the two peaks are different, reflecting different source ion spectra. The inferred parent ions (likely predominantly protons) in the heliosheath also fit to a double-power-law, suggesting that they are pickup ions in the solar wind that have been further energized at the termination shock. We estimate that in the direction of Voyager 2, these ions have an energy density of ~0.8 eV/cm3 from 200 eV to 20 keV, significantly more than the solar wind thermal plasma, and comparable to the "missing" solar wind energy density revealed by the Voyager 2 plasma measurements. They also have ~60% the density of the solar wind. Thus, pickup protons contain most of the termination shock heating energy and dominate the pressure in the heliosheath.

Affiliated with

Also associated with

No associations

Rating

STEREO Observations of Energetic, ~4- 20 keV Neutral Atoms from the Heliosheath does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with STEREO Observations of Energetic, ~4- 20 keV Neutral Atoms from the Heliosheath, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and STEREO Observations of Energetic, ~4- 20 keV Neutral Atoms from the Heliosheath will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1399287