Table Of ContentMAGNETOSPHERIC IMAGING - THE IMAGE PRIME MISSION
MAGNETOSPHERIC IMAGING - THE IMAGE PRIME MISSION
Edited by
J.L. BURCH
Southwest Research Institute, San Antonio, Texas, U.S.A.
Reprinted from Space Science Reviews, Volume 109, Nos. 1-4,2003
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TABLE OF CONTENTS
Foreword vii
J.L. BURCH / The First Two Years of Image
B.R SANDEL, J. GOLDSTEIN, D.L. GALLAGHER and M. SPASO
JEVIC / Extreme Ultraviolet Imager Observations of the Structure
and Dynamics of the Plasmasphere 25
M.B. MOLDWIN, B.R. SANDEL, M.E THOMSEN and Re. ELPHIC
/ Quantifying Global Plasmaspheric Images with in situ Observations 47
D.G. MITCHELL, P.e. BRANDT, E.e. ROELOF, D.e. HAMILTON,
K.e. RETTERER and S. MENDE / Global Imaging of 0+ from
Image/HENA 63
M.-e. FOK, T.E. MOORE, G.R WILSON, J.D. PEREZ, X.X. ZHANG,
P.e. BRANDT, D.G. MITCHELL, E.e. ROELOF, J.-M. JAHN, e.J.
POLLOCK and R.A. WOLF / Global ENA Image Simulations 77
J.U. KOZYRA and M.W. LIEMOHN / Ring Current Energy Input and
Decay 105
D.N. BAKER / Telescopic and Microscopic views of the Magnetosphere:
Multispacecraft Observations 133
C.J. POLLOCK, P.e. BRANDT, J.L. BURCH, M.G. HENDERSON,
J.-M. JAHN, D.J. MCCOMAS, S.B. MENDE, D.G. MITCHELL,
G.D. REEVES, E.E. SCIME, RM. SKOUG, M. THOMSEN and
P. VALEK / The Role and Contributions of Energetic Neutral Atom
(ENA) Imaging in Magnetospheric Substorm Research 155
J.L. GREEN and B.W. REINISCH / An Overview of Results from RPI
on Image 183
S.B. MENDE, H.U. FREY, T.J. IMMEL, J.-C. GERARD, B. HUBERT
and S.A. FUSELIER / Global Imaging of Proton and Electron
Aurorae in the Far Ultraviolet 211
H.U. FREY, S.B. MENDE, T.J. IMMEL, J.-e. GERARD, B. HUBERT,
S. HABRAKEN, J. SPANN, G.R GLADSTONE, D.V BISIKALO
and VI. SHEMATOVICH / Summary of Quantitative Interpretation
of Image Far Ultraviolet Auroral Data 255
S.A. FUSELIER, S.B. MENDE, T.E. MOORE, H.U. FREY, S.M.
PETRINEC, E.S. CLAFLIN and M.R COLLIER / Cusp Dynamics
and Ionospheric Outflow 285
J. BERCHEM, S.A. FUSELIER, S. PETRINEC, H.U. FREY and
J.L. BURCH I Dayside Proton Aurora: Comparisons Between Global
MHD Simulations and Image Observations 313
T.E. MOORE, M.R. COLLIER, M.-C. FOK, S.A. FUSELIER,
H. KHAN, W. LENNARTSSON, D.G. SIMPSON, G.R. WILSON
and M.O. CHANDLER I Heliosphere-Geosphere Interactions Using
Low Energy Neutral Atom Imaging 351
Foreword
The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) is a NASA
Explorer mission that is the first space mission dedicated to imaging of the Earth's
magnetosphere. IMAGE was launched from Vandenberg AFB into an elliptical
polar orbit by a Delta II launch vehicle on March 25, 2000. The two-year prime sci
entific mission of IMAGE began on May 25, 2000 after instrument commissioning
was successfully completed. IMAGE has now been approved for operation until
October 1,2005, and an additional two-year extension is now being considered by
NASA.
The papers in this volume represent many of the scientific results obtained dur
ing the IMAGE prime mission and include some of the early correlative research
with ground-based measurements, measurements from other spacecraft such as
Cluster II, and relevant theory and modeling programs. All of the reported work
is related to the overall IMAGE science objective: How does the magnetosphere
respond globally to the changing conditions in the solar wind? IMAGE addresses
this question with multi-spectral imaging of most of the important plasma pop
ulations of the inner magnetosphere, combined with radio sounding of gradients
of total plasma content. The new experimental techniques fall into the following
areas: neutral atom imaging (NAI) over an energy range from 10 eV to 500 keY
for detection of ionospheric outflow, the plasma sheet, and the ring current; far
ultraviolet (FUV) imaging at 121-190 nm for detection of precipitating protons and
the global aurora; extreme ultraviolet (EUV) imaging at 30.4 nm for measurement
of He+ densities throughout the plasmasphere; and radio plasma imaging (RPI)
over the density range from 0.1-105 cm-3 for the mapping of plasma gradients and
boundaries throughout the inner magnetosphere.
Scientific results from the two-year prime mission include the confirmation with
EUV imaging of the longstanding theory of plasmaspheric tails and the discovery
of plasmaspheric "shoulders" and their cause (south-to-north transitions of the
interplanetary magnetic field, IMF). The surprising finding that cold plasma at
radial distances between two and three Earth radii most frequently rotates at a
rate that is roughly 85-90% of the corotation rate demands revision of the long
held conventional wisdom that the main body of the plasmasphere simply corotates
with the Earth. High-energy NAI has shown how the ring current develops first in
the midnight-to-dawn sector during magnetic storms as opposed to the expected
midnight-dusk partial ring current that has historically been deduced from ground
based magnetometer data. This result was predicted twenty years earlier by global
convection models but could not be tested until ring-current imaging was made pos
sible by IMAGE. The high-energy NAI data also show that energetic ionospheric
oxygen ions are injected into the ring current primarily during substorms that oc-
cur during magnetic storms while the hydrogen content varies more gradually in
concert with the Dst index. Conversely, low-energy NAI has shown global-scale
ionospheric outflow in the 10-500 eV energy range to be an immediate response to
solar-wind pressure pulses. Low-energy NAI has also provided the first measure
ments of solar-wind and interstellar neutral atoms from inside the magnetosphere.
The first global imaging of proton auroras with FUV has allowed the identification
of the ionospheric footprint of the polar cusp and its response to changes in the
IMF. A well-defined almost circular auroral spot at latitudes above the dayside
auroral oval was found to map directly to the magnetopause site of magnetic recon
nection when the IMF was northward. Detached sub auroral proton arcs have been
discovered with FUV and are found to appear in the afternoon sector following
south-north and east-west-rotations ofthe IMF, which cause a poleward contraction
and a dawnward shift of the main proton auroral oval, respectively, as predicted in
1985. Radio sounding has revealed the internal structure of the plasmasphere and
identified plasma cavities as the source of kilometric continuum radiation. These
and numerous other scientific results now set the stage for the extended mission of
IMAGE in which the imaging perspective will change markedly as apogee moves
from the northern polar regions toward the equator and ultimately into the southern
polar cap. The extended mission will occur in the declining phase of the solar cycle
during which the mostly CME-driven magnetic storms of solar maximum (during
the prime mission) will gradually be replaced by recurrent storms associated with
corotating interaction regions.
J.L. Burch
Southwest Research Institute
San Antonio, TX USA
THE FIRST TWO YEARS OF IMAGE
1. L. BURCH
Southwest Research Institute
San Antonio. TX 78228-0510. U.S.A.
Abstract. The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) is the first satellite
mission that is dedicated to imaging the Earth's magnetosphere. Using advanced multispectral ima
ging techniques along with omnidirectional radio sounding, IMAGE has provided the first glimpses
into the global structure and behavior of plasmas in the inner magnetosphere. Scientific results from
the two-year prime mission include the confirmation of the theory of plasmaspheric tails and the
discovery of several new and unpredicted features of the plasmasphere. Neutral-atom imaging has
shown how the ring current develops during magnetic storms and how ionospheric ions are injected
into the ring current during substorms. The first global imaging of proton auroras has allowed the
identification of the ionospheric footprint of the polar cusp and its response to changes in the inter
planetary magnetic field. Detached subauroral proton arcs have been found to appear in the afternoon
sector following south-north and east-west rotations of the IMF. Low-energy neutral atom imaging
has shown global-scale ionospheric outflow to be an immediate response to solar-wind pressure
pulses. Such imaging has also provided the first measurements of solar wind and interstellar neutral
atoms from inside the magnetosphere. Radio sounding has revealed the internal structure of the
plasmasphere and identified plasma cavities as the source of kilometric continuum radiation. These
and numerous other scientific results now set the stage for the extended mission of IMAGE in which
the imaging perspective will change markedly owing to orbital evolution while the magnetospheric
environment undergoes a transition from solar maximum toward solar minimum.
1. Introduction
IMAGE is the first satellite mission dedicated to imaging the Earth's magneto
sphere and is the first mission to achieve global multispectral imaging of magneto
spheric plasmas with time scales relevant to the development of substorms (Burch,
2000). The overall science objective of IMAGE is to determine the response of
the Earth's magnetosphere to changing conditions in the solar wind. IMAGE ad
dresses this objective by seeking the answers to three specific science questions: 1.
What are the dominant mechanisms for injecting plasma into the magnetosphere on
sub storm and magnetic storm time scales? 2. What is the directly driven response
of the magnetosphere to solar wind changes? and 3. How and where are plasmas
energized, transported, and subsequently lost during storms and substorms?
Table I lists the six imaging instruments that were designed to address these
questions. The new imaging techniques include ultraviolet detection of helium
ions and energetic hydrogen atoms; neutral atom imaging in three different en
ergy ranges that encompass ionospheric outflow, solar-wind injection, and trapped
Space Science Reviews 109: 1-24,2003.
© 2003 Kluwer Academic Publishers.
2 J. L. BURCH
TABLE I
IMAGE Science Instruments
Imager Lead Investigator Objectives Measurements
LENA Thomas E. Moore Image Ionospheric Neutral atom composition and flux
NASAlGSFC outflow. at 10 e V to 1 ke V with field of view
of 90° x 360° , angular resolution of
8°, and energy resolution of 80%
MENA Craig J. Pollock Image inner region Neutral atom composition and flux
Southwest Research of plasma sheet. at 1 keY to 50 keY with field of
Institute view of 90° x 120°, angular resolu
tion of 8°, and energy resolution of
80%
HENA Donald G. Mitchell Image ring current. Neutral atom composition and flux
Johns Hopkins Univ., at 20 ke V to 500 ke V with field of
Applied Physics view of 90° x 107°, angular resolu
Laboratory tion of 8°, and energy resolution of
80%
EUV Bill R. Sandel Image Extreme ultraviolet irradiance at
University of Arizona plasmasphere. 30.4 nm with field of view of 90° x
90° and angular resolution of 0.6°
FUV Stephen B. Mende Image electron and Far ultraviolet irradiance at
University of Califor- proton aurora; map 135.6 nm, 121.8 nm, and 140--
nia, Berkeley geocorona. 190 nm with field of view of 15°
and angular resolution of 0.1 0;
geocorona maps with three 1°
field-of-view photometers
RPI Bodo W. Reinisch Sound-total plasma Sound total plasma density gradi
University of Massa density gradients ents throughout inner magneto
chusetts, Lowell throughout inner sphere. Transmit and receive ra
magnetosphere. dio waves with frequencies between
3 kHz and 3 Mhz.
radiation; and radio sounding, which remotely determines total electron density.
Table I also illustrates the measurement capabilities of each instrument. After two
years of operation, each instrument continued to perform well and to contribute to
the science objectives in a significant way.
Specific scientific achievements of the IMAGE mission during its first two years
of operation include:
1. Determination of the spatial extent and location of the polar cusp as functions
of the interplanetary magnetic field (Fuselier et al., 2002a, 2003; Frey et al.,
2002).
THE FIRST TWO YEARS OF IMAGE 3
2. Observation of prompt outflow of ionospheric ions following the arrival of
a CME, indicating the existence of direct heating of the topside ionosphere
(Fuselier et al., 2001; Moore et al., 2001).
3. Identification of global-scale ionospheric outflow as an immediate response to
solar-wind pressure pulses (Fuselier et at., 2002b, 2003);
4. Confirmation of the theory of plasmaspheric tails (Burch et al., 200Ia);
5. Discovery of several new and unpredicted features of the plasmasphere includ
ing "shoulders", "fingers", corotating "voids", and isolated flux tubes (Burch
et at., 2001b; Sandel et al., 2001);
6. The use of solar wind data and the Magnetospheric Specification Model to re
late the plasmasphere shoulders to south-north transitions in the interplanetary
magnetic field (Goldstein et al., 2002);
7. Discovery of subauroral proton arcs and identification of the role of the IMF
in their formation (Immel et al., 2002; Burch et al., 2002);
8. Determination of the energy-dependent injection and drift of energetic ions
during magnetospheric substorms (Burch et al., 200Ia;);
9. Acquisition of the first global images of the geomagnetic storm ring current,
thereby identifying the development of a symmetric ring current during the
recovery phase (Burch et at., 2001a; Mitchell et al., 2001; Pollock et al., 2001).
10. Acquisition of global images of substorm dipolarization in the plasma sheet.
(Brandt et al., 2002);
11. Clarification of the relationships between substorms and magnetic storms, e.g.,
0+ injection into ring current caused by substorms (Mitchell et al., 2003);
12. Acquisition of the first global images of the proton aurora, establishing its
cause and effect with correlative measurements of proton precipitation on FAST,
and determination of the dynamical relationship between electron and proton
aurora during substorms (Frey et at., 2001; Mende et al., 2001);
13. The first remote measurements of plasmaspheric densities using radio sound
ing (Reinisch et al., 2001);
14. Identification of plasmaspheric cavities as source regions for kilo metric con
tinuum radiation (Green et at., 2002);
IS. The first measurements of solar-wind neutral atoms and interstellar neutral
atoms from inside the magnetosphere. (Moore et al., 2001, 2003; Collier et al.,
2001).
The early results from IMAGE represent significant progress toward answering
the mission's scientific objectives. All of the instruments have contributed signi
ficantly to the scientific achievements of IMAGE in no small part because of the
integrated nature of the payload and the resulting data stream, which uses a com
mon format that facilitates the joint plotting of data. IMAGE has also contributed to
the NOAA space forecasting activity through the ancillary real-time transmission
of the entire IMAGE data set in addition to its baseline store-and-forward data
mode.
