Advanced Composition Explorer (ACE) Particle Composition and Flux Browse Data

The Advanced Composition Explorer (ACE) is an Explorer mission that is
being managed by the Office of Space Science Mission and Payload
Development Division of the National Aeronautics and Space
Administration (NASA). The primary purpose of ACE is to determine and
compare the isotopic and elemental composition of several distinct
samples of matter, including the solar corona, the interplanetary
medium, the local interstellar medium, and Galactic matter.

The ACE spacecraft measures the flux of charged particles from solar
wind energies (300 km/sec) up through galactic cosmic rays (500
MeV/nucleon) and the interplanetary magnetic field upstream of
earth. The ACE data includes energetic particles from solar wind
cosmic ray energies. In addition, this data set covers both atomic
and isotopic composition data for most energy ranges. This pace data
is at L1 (approx. 1.5 million km upstream along earth-sun line).

ACE browse data are designed for monitoring large scale particle and field
behavior and for selecting interesting time periods. The data are automatically
generated from the spacecraft data stream using simple algorithms provided by
the instrument investigators. They are not routinely checked for accuracy and
are subject to revision. Use these data at your own risk, and consult with the
appropriate instrument investigators about citing them.

Browse parameters are a subset of measurements by the ACE instruments which are
created at the Science Center during level one processing. They are delivered
to the public domain as soon as possible. Their purpose is to allow monitoring
of the solar wind and large-scale particle and magnetic field behavior, and
selection of interesting time periods for more intensive study. Interesting
time periods might include solar energetic particle events, or the passage of
an interplanetary shock. An additional use of the browse parameters is to
investigate relationships between the data from the various ACE instruments,
and between ACE data and data from other sources.

The browse parameters include unsectored fluxes of ions at many different
energies and electrons at a few energies. They also include the interplanetary
magnetic field, and solar wind parameters such as proton speed and temperature.
They therefore furnish a very abbreviated description of what is being observed
by the ACE instruments, without the relatively high cost of storing and
analyzing all the level one data. Eventually they may be supplemented with
event data from the particle detectors, but experience with the flight data is
a prerequisite for delivering useful products of that type.

See: http://www.srl.caltech.edu/ACE/ASC/browse/browse_info.html
for more information.