Statistics of Flow Channels Observed as Regions of Ion Heating in
Energetic Neutral Atom Images
Abstract
Reconnection in the magnetotail transfers magnetic energy to thermal and
kinetic energy in ions and electrons. These particles are injected both
Earthward and tailward from the reconnection region. The Earthward
particles are transported to the inner magnetosphere where they drive
the ring current and radiation belts. The injections are observed in the
plasma sheet in conjunction with dipolarizations of the magnetic field.
The particles have been found to travel within narrow flow channels,
rather than broadly across the magnetotail, in spatially and temporally
localized events known as bursty bulk flows (BBF). Simulations of such
events show these narrow flow channels moving from the reconnection
region to the injection region. However, global observations are needed
to understand how BBFs connect the reconnection region and the inner
magnetosphere during storms and substorms. Ion heating has been observed
with in situ measurements at the reconnection region and within the
dipolarization fronts and BBFs. Using energetic neutral atom (ENA)
imaging, ion temperature maps can be calculated to provide such global
observations. Regions of ion heating have been observed in these maps
and comparisons with in situ measurements demonstrate that they are
associated with these phenomena. An automated identification algorithm
has been developed and run on our database of storm-time ion
temperatures. We will present the results of case and statistical
studies of the characteristics of these features.