The Spatial Distribution of Upstream Ion Events Measured by ACE, Wind, and STEREO Near the Earth's Bow Shock

Details The Spatial Distribution of Upstream Ion Events Measured by ACE, Wind, and STEREO Near the Earth's Bow Shock The Spatial Distribution of Upstream Ion Events Measured by ACE, Wind, and STEREO Near the Earth's Bow Shock

Dec 2007

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007agufmsh52b..02d&link_type=abstract

American Geophysical Union, Fall Meeting 2007, abstract #SH52B-02

Mathematics

Probability

2114 Energetic Particles (7514), 2134 Interplanetary Magnetic Fields, 2154 Planetary Bow Shocks, 2784 Solar Wind/Magnetosphere Interactions

Scientific paper

Abrupt enhancements in the intensities of ions in the energy range of a few 10s of keV to 100s of keV upstream of the Earth's Bow Shock -- upstream ion events -- are characterized by short durations (~1-2 hours), steeply falling spectra, large (>100:1) field-aligned sunward anisotropies, and positive correlations with the solar wind speed and geomagnetic indices. Despite the wealth of information available, however, it is still not clear whether these ions are accelerated at the bow shock or somewhere inside the Earth's magnetosphere. Furthermore, such events are also often observed simultaneously at two or more spacecraft, perhaps indicating that a large source region covering the entire size of the bow shock fills large spatial structures in the upstream region. In this paper we use simultaneous measurements of >40 keV upstream ions observed at ACE, Wind, and STEREO-A between 2007, day 1 through 2007, day 181 to calculate the occurrence probability of upstream events as a function of lateral and radial separation between L1 and STEREO-A. During the end of this ~6- month period, Wind (or ACE) and STEREO-A were separated by ~1750 RE in the radial direction and laterally in YGSE by ~3800 RE. Despite this large separation, STEREO-A continued to observe upstream events right up until the end of our survey period. More surprisingly, we found that the occurrence probability for measuring simultaneous upstream events at Wind or ACE at L1 and STEREO-A was ~20- 30%, i.e., far greater than that expected from accidental coincidences. We discuss the implications of these results for the size of the source region, the conditions under which upstream events occur, and the size and nature of the spatial structures in which these ions populate and propagate in the upstream region.

Affiliated with

Also associated with

No associations

Rating

The Spatial Distribution of Upstream Ion Events Measured by ACE, Wind, and STEREO Near the Earth's Bow Shock 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 The Spatial Distribution of Upstream Ion Events Measured by ACE, Wind, and STEREO Near the Earth's Bow Shock, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Spatial Distribution of Upstream Ion Events Measured by ACE, Wind, and STEREO Near the Earth's Bow Shock will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1419241