Analysis of Suprathermal Events Observed by STEREO/PLASTIC with a Focus on Upstream Events
Abstract
Since the late 1960's, suprathermal and energetic ion events with energies ranging from just above the solar wind energies up to 2MeV and lasting for several minutes to hours, have been detected upstream of the Earth. Possible sources of these ions include magnetospheric ions, solar wind ions accelerated between the Earth's bow shock and hydromagnetic waves to energies just above the solar wind energies, and remnant ions from heliospheric processes (such as Solar Energetic Particle (SEP) events or Corotating Interaction Regions (CIRs)). The unique orbits of both STEREO spacecraft, STEREO-A (STA) drifting ahead in Earth's orbit and STEREO-B (STB) lagging behind in Earth's orbit, allow for analysis of upstream events in these unexamined regions. Using both the PLASTIC and IMPACT instruments on board STA/B we can examine protons in the energy range of solar wind energies up to 80keV, their spatial distribution, and attempt to determine if the spacecraft is magnetically connected to the Earth's bow shock. Suprathermal events observed by STEREO/PLASTIC on STA during solar minimum conditions are examined for possible upstream events using anisotropy measurements, velocity dispersion, magnetic connection to the bow shock, and frequency of events as a function of time and distance.
- Publication:
-
Solar Heliospheric and INterplanetary Environment (SHINE 2009
- Pub Date:
- August 2009
- Bibcode:
- 2009shin.confE..94B