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Proposed Projects
The Radiation Belt Storm Probes (RBSP) Mission (launch date 2012):
The UMN proposal for an Electric Field and Search Coil (EFASC) Instrument Suite on the
NASA RBSP mission
Recently, the University of Minnesota Space Plasma Physics Group proposed to NASA
for an instrument to measure electric fields and
high frequency magnetic fields to fly on the Radiation Belt Storm Probe (RBSP)
Mission. Selections have recently been announced and the main portion of the EFASC
proposal, the Electric Field Instrument (EFI), has been selected. (A search coil instrument
will also be flown on the mission by a collaboration headed by Dr. Craig Kletzing for the University of Iowa.)
The Principle Investigator of the EFASC/EFI proposal is Professor John Wygant. Collaborating
institutions include the University of California, Berkeley, the University of
California, Los Angeles, the University of Colorado, Boulder, Dartmouth College,
University of Alberta in Canada, the Air Force Research Laboratory in Lexington
Massachusetts, and Massachusetts Institute of Technology. The RBSP mission consists
of two spacecraft designed to investigate the plasma physics mechanisms responsible
for episodic intervals of intense charged particle energization in the Earth's
radiation belts. Some of these mechanisms include shocks, large-scale oscillating
wave fields, injection fronts, electric fields associated with large scale flow of
plasma, and interactions with higher frequency waves. These mechanisms can
increase energetic particle fluxes by factors of hundreds to millions over periods of seconds
to days. The RBSP spacecraft will also be equipped with instruments designed to
measure the energetic electrons and protons, as well as low frequency magnetic fields
built by other groups of experimenters around the country. The purpose of the RBSP
mission is to provide both a conceptual and quantitative understanding of these
energization mechanisms. Many of these same processes are believed to operate at the
planetary magnetospheres of magnetized planets such as Jupiter, Saturn, Neptune, and
Uranus. There is strong evidence these energetic particles can result in spacecraft
problems ranging from momentary operational malfunctions to reduction in spacecraft
lifetime, and, in some cases, complete spacecraft loss.
Active Projects
The STEREO Mission (launch date late-summer 2006):
The Solar TErrestrial RElations Observatory (STEREO) is a two spacecraft mission in which the spacecraft are placed in
orbit around the sun at the same distance as the Earth with one spacecraft
ahead of the Earth and one spacecraft trailing. The purpose of the two
separated spacecraft is to provide a stereoscopic view of solar flares and
coronal mass ejections, as they gradually develop on the surface of the sun
and then erupt explosively into interplanetary space. These processes are
associated with energization of particles to extremely high energies. In
addition, on their journey to the outer reaches of the solar system,
coronal mass ejects can encounter the Earth's magnetosphere where they drive
major geomagnetic storms. These structures are powerful generators of energetic
particles and radio waves which can be detected during both the explosive phases
of the eruptions and while they plow through the interplanetary medium. These
radio waves are thought to be generated where energetic particles are being
accelerated and provide important insights on the different acceleration
mechanisms involved. The University of Minnesota (Keith Goetz, Paul Kellogg,
Steve Monson, and Cindy Cattell), in collaboration with a French team from the
Observatory of Paris in Meudon and a team from NASA's Goddard Space Flight
Center is responsible for the plasma and radio waves instrument to be flown on
the STEREO spacecraft (SWAVES). Keith Goetz is responsible for the hardware
design and development. The SWAVES instrument will measure plasma and radio waves
at frequencies ranging up to 32 MHz, including waveform capture sampling to
examine nonlinear waves. Another instrument, IMPACT, lead by a team from U.C.
Berkeley will measure energetic particle fluxes as they travel to the Earth.
The STEREO spacecraft is also equipped with white light coronagraphs built by
the Naval Research Laboratory to view these structures while they are still close
to the sun and PLASTIC, built by the University of New Hampshire, which measures
the composition of ions accelerated during these eruptions.
The Cluster (II) Multi-Spacecraft Mission:
The four-satellite ESA/NASA Cluster Mission was designed study cross-scale
coupling and particle acceleration at magnetospheric boundaries, including the
magnetopause and bow shock, and to examine turbulence in the solar wind. It
was launched in July and August, 2000 into a polar obit with apogee of ~19 Re
(1 Re = 1 earth radii, ~6400 km) and perigee of ~4 Re. The four Cluster
satellites orbit in a tetrahedral formation, designed to separate spatial and
temporal variations, with variable separations from ~500 to 5000 km. The
tetrahedral separation has enabled numerous important discovered related to motion,
orientation and scale-sizes of boundaries and waves. Cluster research at the
University of Minnesota has provided new observations of reconnection in the
magnetotail, including the first measurements of electron inertial scale current
sheets and ballistic acceleration of hydrogen (oxygen) ions by hydrogen (oxygen)
inertial-scale electric potential wells and the first simultaneous observations of
narrow electron beams and electron holes at reconnection sites. Professor John Wygant
participated in the development of the Cluster EFW (Electric Field and Waves) hardware. Professors Cattell,
Kellogg and Wygant are Co-Investigators on the Cluster EFW Instrument. Three current
University of Minnesota Ph.D. students are investigating Cluster observations of
plasma processes in the magnetosphere.
The Fast Auroral SnapshoT (FAST) Mission:
The Fast Auroral SnapshoT (FAST) satellite, launched in August, 1996, was the
second satellite in NASAÆs small explorer program. It was designed to obtain
extremely high time resolution measurements of particles and fields to
explore the physical processes that accelerate particles and create the
visible aurora. FAST examines the natural acceleration processes that occur at
the interface between the cool, dense collision-dominated ionospheric plasma and
the hot, tenuous, colli-sionless magnetospheric plasma. These same acceleration
processes are expected to occur in other similar plasma tran-sition regions, for
example in the atmospheric-magneto-spheric transition around planets such as
Jupiter, Saturn, and Mercury, in the photospheric-coronal transition at our Sun,
and in astrophysical plasmas where intense radio emission indicates processes
similar to the EarthÆs generation of auroral kilometric radiation (AKR). The
FAST mission has revolutionized our view of the aurora and resolved the detailed
plasma interactions that control magnetosphere-ionosphere coupling via waves and
plasma. FAST continues to operate and is the only NASA satellite obtaing
measurement of particles and currents in this important region of space. Professor
Cattell is a FAST Co-Investigator and many University of Minnesota graduate
students and undergraduates have performed research on this data set. Two Ph.D.
students utilized FAST data in their theses.
The Polar Mission:
The NASA Polar satellite, launched in February, 1996, was designed to study
the processes of flow of energy, mass and momentum in the polar regions of the
EarthÆs magnetosphere using twelve instruments, including both visible and UV
imagers and in-situ particles and fields instruments. Intially, apogee (at an
altitude of ~8.5 Re) was over the northern pole and perigee (~1 Re) over the
southern poles. Precession of the orbit resulted in apogee in the equatorial plane,
so that the critical region of the sub-solar magnetopause and the near-earth
magnetotail could be explorered. Research at the University of Minnesota using
Polar data has focussed on magnetic reconnetion and energy flow to power the
aurora, as well as on particle acceleration processes and solitary waves. Professor
John Wygant participated in the development of the Polar Electric Field Instrument
(EFI) and is a Polar EFI Co-Investigator. Professor Cattell in a Co-Investigator on the
EFI and MFE (magnetic field instrument). Four University of Minnesota Ph.D. students
based their Ph.D. thesis substantially on Polar observations. A number of undergraduates
have also been involved in research on Polar data at the University of Minnesota.
The Wind Mission:
The NASA Wind satellite was launched in November, 1994. It was designed to study
plasma processes in the solar wind near 1 AU, to provide coordinated measurements
for satellites studying the solar wind at other radial distances, and to provide
information on the solar wind drivers of magnetospheric activity. Professor Paul
Kellogg and Keith Goetz are Co-investigators on the Wind Waves instrument. The Wind
Waves instrument has provided the data for important new results on Type II and Type
IV radio bursts, non-linear wave-wave interactions and on shocks. The Wind Waves
instrument in the precursor to the STEREO Waves instrument and will provide waves
measurements at a third point for shock and CME propagation studies made by STEREO.
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