Proceedings published in: ST6.CLUSTER II - the first results, Geophysical Research Abstracts (2001) Vol. 3 Alleyne, H.StC., Balikhin, M.A., N., W.S., Yearby, K., Gustafsson, G.G., André , M., Cornilleau-Wehrlin, N. and Décréau, P.M.E.
waves from Cluster
Alleyne, H.StC., Yearby, K., Balikhin, M., Walker, S., Cornilleau-Wehrlin, N., Décréau, P.M.E., Gurnett, D. and Gustafsson, G.
correlative results from the WEC instruments on cluster
André, M., Gustafsson, G., Behlke, R., Carozzi, T., Eriksson, A., Khotyaintsev, Y., Tjulin, A., Vaivads, A., Wahlund, J.-E. and Cornilleau-Wehrlin, N .
of multi-satellite observations of waves
Behlke, R., André, M., Pedersen, A., Opgenoorth, H. and Eglitis, P.
of electric field and wave signatures measured by the Cluster
satellites during magnetopause crossings
Cully, C., André, M., Carozzi, T., Pedersen, A., Jackel, B., Pitout, F., Donovan, E., Opgenoorth, H. and Reme, H.
observations of mesoscale electrostatic structures in the outer
Gustafsson, G.; Ahlen, L.; Eriksson, A. I.; Gunnarsson. H.; Lundgren, A.; Thomas, H.; Berg, P.; Harvey, P.; Khyunge, K.
electric field and wave experiment on Cluster
PS12. Space instrumentation
(co-sponsored by ST and GI), Geophysical Research Abstracts
(2001) Vol. 3
Gustafsson, G., André, M., Alleyne, H. STC., Blomberg, L., Bostrom, R., Carozzi, T., Cattell, C., Cornilleau-Wehrlin, N., P. Décréau, A. Egeland,, A. Eriksson, C-G. Falthammar, R. Grard, D. Gurnett, C. Harvey, B. Holback, G. Holmgren, O. Holter, J. Holtet, P. Kellogg, Y. Khotyaintsev, P. Kintner, S. Klimov), H. Laakso, J-P. Lebreton, P-A. Lindqvist, B. Lybekk, R. Manning, M. Maksimovic, G. Marklund, N. Maynard, J. Moen, F. Mozer, K. Mursula, H. Opgenoorth, A. Pedersen, H. Pecseli, R. Pfaff, B. Popielawska, I. Roth, A. Roux, H. Singer, K. Stasiewicz, R. Schmidt, P. Tanskanen, M. Temerin, O. Thrane, J-E. Wahlund, J. Wygant
overview of early results from the Electric Field and Wave
investigation on Cluster(Solicited Paper).
Gustafsson, G., Mursula, K., Carozzi, T., Lybekk, B., Stasiewicz, K., Tanskanen, P., Singer, H. and Laakso, H.
observations on Cluster
Khotyaintsev, Y., Stasiewicz, K., Eriksson, A. and André, M.
related density structures
Khotyaintsev, Y., Stasiewicz, K. and Khotyaintsev, M.
Visualization of Cluster data with OVT
Laakso, H., Grard, R., Masson, A., Escoubet, P., Lebreton, J.-P. and André, M., et al
between bulk electron densities and potential difference
measurements on the Cluster satellites
Lindqvist, P.-A., Marklund, G., Mozer, F.S., Bale, S., Hull, A., André, M., Gustafsson, G., Eriksson, A. and Pedersen, A.
field and plasma density mesurements at Cluster magnetopause
Marklund, G., Lindqvist, P.-A. , Karlsson, T., André, M. and Gustafsson, G.
for large-amplitude electric field structures using Cluster
multi-point observations near perigee
Moen, J., Holtet, J.A., Pedersen, A., Lybekk, B., Oksavik, K., Østgaard , N. and Gustafsson, G.
observations related to postnoon auroral arcs
Pedersen, A., Décréau, P.M.E., Escoubet, C.P., Gustafsson, G., Laakso, H., Lindqvist, P.-A., Lybekk, B., Mozer, F. and Vaivads, A.
high time resolution information on electron density on Cluster
Pulkkinen, T.I., Palmroth, M. and Ganushkina, N.Y.
magnetospheric modeling and Cluster II observations
Stasiewicz, K., Khotyaintsev, Y., Gustafsson, G., Lindqvist, P.-A., Mozer, F., Eriksson, A. and Carozzi, T.
Alfven waves at the magnetopause
Torbert, R.B., Paschmann, G., Quinn, J., Haerendel, G., Mozer, F.S., André, M., Ericsson, A., Gustafsson, G., Vaith, H., Foersten, M., Georgescu, E., Mcilwain, C., Kern, S.S., Fillius, W., Kletzing, C., Briggs, B., Matsui, H., Lindqvist, P.-A. and Pederse
Cluster stormtime electric fields from EDI and EFW
Bale, S.D., Mozer, F.S., André, M., Ericsson, A.I., Gustafsson, G., Holmgren, G., Lindqvist, P., Holtet, J., Lybekk, B., Pedersen, A., Grard, R., Laakso, H., Mursula., Tanskanen, P. and Yerby, K
EFW measurements of bow shock thickness, speeds, and normals
Bale, S.D., Mozer, F.S., André, M., Ericsson, A.I., Gustafsson, G., Holmgren, G., Lindqvist, P., Holtet, J., Lybekk, B., Pedersen, A., Grard, R., Laakso, H., Mursula., Tanskanen, P. and Yerby, K.
normal, thickness and speed of the dusk magnetopause from Cluster
Electric Field and Wave experiment measurements
McFadden, J. .P., Mozer, F.S., Carlson, C.W., Parks, G., Larson, Bosqued, J.M., Dandouras, I., Reme, H ., Sauvaud, J.A., Balogh, A., Dunlop, M., Décréau, P., Kistler, L., Moebius, E., McCarthy, M., Klecker, B., Bavassano-Cattaneo, M. and Lundin, R.
and comparison of measurements between the particle and field
instruments on Cluster
Torbert, R.B., Paschmann, G., Quinn, J., Mozer, F.S., Mozer, F.S., Kistler, L..., Mouikis, C., Haerendel, G., Puhl-Quinn, P., André, M., Gustafsson, G., Vaith, H., Foerster, M., Georgescu, E., McIlwain, C., Kerr, S..., Kletzing, C., Matsui, H. ; Lindqvist, P.; Pedersen, A., Fillius, W.
of Electric Fields measured by the Electron Drift Instrument(EDI)
and the Electric Field and Waves Instrument (EFW ) on the CLUSTER
Wygant, J. R .; Way, P.; Keiling, A.; Cattell, C. A.; Lysak, R. L.; Temerin, M. A.; Mozer, F. S.; Mende, S.; Parks, G.; Brittnacher, M.; Kletzing, C. A.; Scudder, J. D.; Petersen, W. K.; Russell, C. T.; Spann, J.; André, M.; Toivanen, P.; Lotko, W.; Streltsov, A.
observations of intense electric and magnetic field fluctuations
and associated earthward magnetic field -aligned poynting flux
throughout the plasma sheet at 4-6 Re altitudes during major
André, M.An overview of first results from the electric field and wave investigation on Cluster
Pedersen, A., André, M., Gustafsson, G., Vaivads, A., Bale, S. and Lindqvist, P.A.
electric field measurements at the magnetopause
Roux, A., Le Contel, O., Perraut, S., Robert, P., Cornilleau, N., Gustafsson, G., André, M., Eriksson, A.I. and Wahlund, J.E.
fluctuations measured on board cluster satellites
André, M.The Cluster mission: some results and plans related to electric field observations
observations at the magnetospheric boundaries
Cattell, C.Observations of high and low altitude solitary waves and comparison to theory
Cluster EFW multipoint magnetosheath wave
Measurements of solitary electron holes
André, M., Balogh, A., Cornilleau-Wehrlin, N. and Paschmann, G. Electric Field Investigations by Cluster The four Cluster satellites give a unique opportunity to investigate plasma processes in the terrestrial magnetosphere. Here we summarize some recent findings where electric field observations are of major importance. The results include observations of the magnetopause and the auroral region. Both the motion of large scale (thousands of kilometers) structures as well as wave phenomena at smaller spatial scales (ion gyro radius) are compared and discussed.
Angelopoulos, V., Mozer, F.S., André, M. and Lindqvist, P.
Geotail-CLUSTER Correlative Measurements of Plasma Sheet Poynting Flux During the Course of Substorms
Two fortuitous conjunctions between
Geotail in the equatorial plasma sheet and CLUSTER at ~4Re
altitude on plasma sheet field lines are utilized to study the
evolution of Poynting flux from its source to the aurora.
Increased wave power at both satellites correlates with increased
electrojet and auroral activity. The four Cluster satellites show
qualitatively very similar Poynting fluxes and overall wave
behavior. The differences between the satellites are being used
to characterize the temporal and spatial properties of the
observed waves. Of primary interest is the propagation and
dissipation of the waves along the field lines, which in turn,
depends critically on the perpendicular wavelength and
propagation speed. We discuss ionospheric closure via Alfven
waves or stationary field aligned currents as revealed by
multiple crossings of the same region. We finally explore the
possibility of high altitude dissipation (between CLUSTER and
Geotail), if perpendicular scale-lengths are already on the ion
gyroradius scale size at those altitudes.
Balikhin, M.A., Dunlop, M., S., W., Krasnoselskikh, V., Andre, M., Nozdrachev, M. and Allene, H.
Terrestrial Bow Shock in the Electrostatic Subshock Regime
Scales of the electromagnetic field in the
shock front have been estimated using CLUSTER data. The values of
these scales has allowed us to identify different classes of
collisionless shocks. Based on this identification we have shown
that CLUSTER observed the terrestrial bow shock in the
electrostatic sub-shock regime, which has been studied
theoretically but has only been previously observed in laboratory
plasmas. According to our knowledge it has never been identified
reliably in space plasma. This regime exists in a narrow
parameter range between subcritical shocks and supercritical
Bates, I., Balikhin, M.A. and André, M.
Wave Mode Identification Using Cluster Data
In two satellite data wave-mode
identification is limited by the methods for finding the wave
propagation directions (e.g. minimum variance analysis). These
methods put strong limitations on the properties of the observed
waves. The Cluster-II mission allows the directions to be found
without the limitations imposed by MVA. This enables
identification of wave modes observed in the electric field
components. Such an identification was carried out for low
frequency waves observed in the magnetosheath by EFW.
Behlke, R., André,M., Buchert, S., Schwartz, S., Dunlop, M., Lucek, E., Balogh, A. and Mann, G.
Multi-Spacecraft Measurements of the Electric Field of Short Large Amplitude Magnetic Structures (SLAMS)
Short Large Amplitude Magnetic Structures
(SLAMS) are observed in the upstream region of the quasi-parallel
region of the Earth's bow shock. They seem to grow out of the
upstream ULF wave field and associated diffusive ions in the
foreshock. While convected with the solar wind, SLAMS decelerate
and heat the flow. Thus, the quasi-parallel bow shock region
could be considered as a patchwork of SLAMS. We present
multi-spacecraft measurements of the electric field in SLAMS and
the ULF wave field obtained by CLUSTER with the highest
instruments' resolution. The relation between both the ULF waves
and SLAMS is studied. Furthermore, the shapes and sizes of SLAMS
and their spatial distribution are investigated.
Cattell, C.A., Dombeck, J., Kimkhan, K.H., Wygant, J.R., Mozer, F.S., André, M. and Elphic, R.C.
Observations of Solitary Waves and Wave Packets by Cluster
Solitary waves have, for the first time,
been identified in the Polar 3d electric field data at the
subsolar, equatorial magnetopause. These nonlinear, bipolar
electric field pulses parallel to the magnetic field occur both
as individual spikes and as trains of spikes. The solitary waves
have amplitudes up to 25 mV/m, and velocities from 150 km/s to
>2000 km/s, with scale sizes the order of a kilometer
(comparable to the Debye length). Almost all the observed
solitary waves are positive potential structures with potentials
of 0.1 to 5 Volts. They are often associated with very large
amplitude waves in either or both the electric and magnetic
fields. Although most of the observed signatures are consistent
with an electron hole mode, the events with very low velocities
and the few negative potential structures may be indicative of a
second type of solitary wave in the magnetopause current layer.
The solitary waves may be an important source of dissipation and
diffusion at the magnetopause.
Cornilleau-Wehrlin, N., Chanteur, G., Perraut, S., Rezeau, L., Robert, P., Roux, A., Sahraoui, F., Belmont, G., Chust, T., Le Contel, O., Maksimovic, M., Hubert, D., Lacombe, C., Lefeuvre, F., Parrot, M., Pincon, J., Décréau, P.M., Harvey, C.C. , Louarn, P., Kofman, W., Santolik, O., Gurnett, D. A., Alleyne, H.S., Gough, M.P., André, M., Gustafsson, G., Pedersen, A., Roth, M., Pellinen, R., Balogh, A.
First Results of the Spatio-Temporal Analysis of Field Fluctuations Experiment (STAFF) of Cluster
STAFF experiment is one of the five
experiments which constitute the Cluster Wave Experiment
Consortium (WEC). STAFF consists of a three-axis search coil
magnetometer to measure magnetic fluctuations at frequencies up
to 4 kHz, a wave form unit (up to either 10 Hz or 180 Hz) and a
spectrum analyzer (up to 4 kHz) (Cornilleau-Wehrlin et al, 1997).
The spectrum analyzer combines the 3 magnetic components of the
waves with the two electric components measured by EFW to
calculate in real time the 5  5 Hermitian
cross-spectral matrix at 27 frequencies distributed
logarithmically in the frequency range 8 Hz to 4 kHz. The time
resolution varies between 0.125s and 4s. Different tools have
been prepared (Cornilleau et al., 2000), specific to the Cluster
related studies. The first results presented will show the
capabilities of the experiment in different key regions of the
magnetosphere-solar wind system encountered by Cluster, using
different specific tools.
Ericsson, A.I., André, M., Behlke, R., Tjulin, A. and Vaivads, A.
Magnetopause Waves: Cluster ResultsMagnetopause Waves: Cluster Results
Waves and fluctuations are of fundamental
interest for understanding transport processes across the
magnetopause. The four Cluster spacecraft have provided
unprecedented possibilities to study the stability and
localization of these processes. We present a study of waves in
the 10 Hz frequency range, based on electric field data from the
EFW instrument and supported by magnetic data from STAFF and FGM
instruments. Our examples show general similarity over the length
scale of the satellite separation (500 - 1000 km), with the
strongest electric field signatures apparently localized to
scales comparable to the ion gyroradius.
Gustafsson, G., Wahlund, J.E., Stasiewicz, K., André, M., Ericsson, A.I., Laakso, H., Mozer, F. , Lindqvist, P. and Pedredersen, A.
Electric Field and Density Observations of Small-Scale Plasma Structures on Cluster
The four-point measurements by Cluster
are well adapted to study small-scale plasma structures in the
plasma regions of the magnetosphere out to the solar wind. A new
probe environment constructed for the Cluster electric field
experiment produces electric field and spacecraft potential
(density) data of very high quality. The observations used in
this study are based on the period when the spacecraft had a
separation of about 600 km in the tetrahedron configuration and
apogee was on the dayside of the Earth. Data from the four
spacecraft show that signatures in the electric field with high
coherence are frequently observed for timescales of tens of
seconds or longer in many plasma regions along the orbit. Both
periodic waveform and solitary structures are observed. The three
dimensional characteristics of the various events and their
possible sources will be discussed.
Marklund, G.T., Karlsson, T., Ivchenko, N., Lindqvist, P., André, M., Buchert, S., Gustafsson, G. and Vaivads, A.
Auroral Electric Fields Observed by Cluster Near Perigee
Results are presented on auroral electric
field structures using Cluster data obtained near perigee, where
the four Cluster spacecraft are aligned as pearls on a string.
Intense highly structured electric fields are frequently observed
on auroral field lines by Cluster during substorm activity. The
scale sizes are typically 5-20 km (at the ionospheric level) and
field magnitudes up to 150 mV/m are observed. With a time
separation of a few minutes between the four satellites the
temporal evolution and stability of the structures can be
investigated in detail. The stability of the structures is found
to depend strongly on the substorm activity level. During oval
expansion the structures are very dynamic and change shape and
polarity but otherwise the structures can be fairly stable over
100 s.The more stable structures are associated with
field-aligned currents and energetic electron transition regions
associated with steep gradients in the satellite potential. For
the more stable structures it is likely that they represent the
high-altitude extension of quasi-stationary auroral potential
structures. The Cluster data may further be used to reveal the
specific form of the auroral potential structures and their
Masson, A., Moullard, O., Laakso, H., Grard, R., André, M., Decreau, P. and Cornilleau-Wehrlin, N.
2-D MHD turbulence in the vicinity of the plasmapause
The CLUSTER quartet crosses the plasmasphere
once per orbit when the geomagnetic activity is not too high. In
this case, the plasmasphere may shrink to altitudes below L=4.
The plasmapause, the boundary between the plasmasphere and the
magnetosphere, is often considered to correspond to a step-like
density drop out (around 1000 e-/cc in the plasmasphere and 1
e-/cc outside), which fits to the image of a dense and smooth
electron density "doughnut" around the Earth. But, as
observed by CLUSTER, the reality is more complex: large density
fluctuations are observed inside the plasmasphere or at the
plasmapause. We have analyzed these large fluctuations on the
Spacecraft Potential, considered as a proxy of the electron
density, measured by the Electric Field and Waves instrument. The
WHISPER relaxation sounder is used for calibration below 100
e-/cc. A companion presentation on this subject will be made by
O. Moullard. We check for the presence of 2-D MHD turbulence.
Such turbulence could be produced by velocity shear at the flow
separatrix, which can be detected using the electric field data.
As a unique feature of CLUSTER, the use of the four satellites
facility allows to investigate the spatial extension and the
temporal evolution of this turbulence. Finally, the relation
between these large amplitude fluctuations and low frequency
emissions observed by STAFF are investigated.
Moullard, O., Masson, A., Laakso, H., André, M., Cornilleau-Werhlin, N. and Decreau, P.
Plasma waves observed during plasmapause crossings
Different types of plasma waves are observed
during plasmapause crossings with the 4 CLUSTER satellites. Using
WHISPER, STAFF and EFW data, we investigate the electromagnetic
and electrostatic waves with frequency below the electron
cyclotron frequency (fce), at fce (10-15 kHz), between harmonics
of fce, and at near the plasma frequency (fp, 20-220 kHz). The
waves are interpreted with respect to local density structures
that have steep density gradients covering up to a few hundreds
per cm3. Each of these density enhancements corresponds to an
incursion into a plasmaspheric like plasma. Below the WHISPER
observation limit, 80 kHz, the plasma density is inferred from
the local fp emission and is used to obtain a relationship
between spacecraft potential and density. Above 80 kHz, this
relationship serves to determine fp from the spacecraft
potential. Thus a density measurement is provided in a region
where often particle instruments do not operate. Attempts are
made to identify and inter-relate the observed waves using
multi-point analysis. An interpretation on the density structures
and the low frequency electromagnetic waves is also proposed in a
companion paper (A. Masson et al.).
Mursula, K., Penttinen, K., André, M., Gustafsson, G., Bale, S., Mozer, F. and Cornilleau-Werhlin, N.
Observations of Electromagnetic Ion Cyclotron Waves Onboard the Cluster Satellites
The electric field and wave (EFW)
instrument on board the four Cluster satellites samples normally
25 samples of the two spin-plane components of the electric field
per second. This covers the whole frequency range of
electromagnetic ion cyclotron (EMIC) waves, allowing unique
possibilities to study these waves in the different parts of the
magnetosphere, magnetosheath and solar wind, and within their
boundary layers. Observations at the four Cluster satellites give
information about the conditions of EMIC wave generation, the
spatial extent of the wave source and its temporal development as
well as wave propagation. We will present here examples of EMIC
waves observed by the EFW instrument in the different regions and
compare the EFW observations with simultaneous waves observed on
Persoon, A., Gurnett, D., Pickett, J., Canu, P., Decreau, P., Laakso, H., Pedersen, A., André, M., Parks, G., Wilber, M., Reme, H., Goldstein, M. and Fazerkerley, A.
Multipoint Plasma Density Measurements from Cluster Wave and Particle Instruments
Measurements from instruments onboard the
Cluster spacecraft are used to study regions of diminished plasma
density inside and poleward of the nightside auroral zone. The
plasma density is derived from the digitization of the electron
plasma frequency cutoff of the whistler mode auroral hiss, using
the electric field spectrum measurements from the Wideband Plasma
Wave Instrument (WBD). Two nightside auroral zone crossings, on
May 8 and July 21, 2001, each with simultaneous measurements from
two Cluster spacecraft, have been selected for this study. Both
of these intervals contain multiple low density structures and
provide an opportunity to make multi-instrument comparisons of
the WBD electric spectrum measurements with the electron plasma
frequency measurements of the WHISPER experiment and the
spacecraft potential measurements of the Electric Fields and
Waves (EFW) experiment. Since the satellite potential
measurements are very sensitive to variations in the electron
density, EFW spacecraft potential and density measurements will
complement the WBD density measurements in the low density
regions. Density variations will also be compared to the observed
ion fluxes, using the ion distribution functions of the Cluster
Ion Spectrometry (CIS) instruments and the low energy electron
fluxes, using the electron velocity and energy distributions of
the Electron and Current Experiment (PEACE).
Roux, A.F., Fontaine, D., Le Contel, O., Perraut, S., Robert, P., Cornilleau-Wehrlin, N., Sauvaud, J.A., Reme, H., André, M. and Balogh, A.
Multipoint and Multi-instrument Study of a Flux Transfer Event Crossing: Preliminary Results
Data from several instruments on Cluster
(PEACE, CIS, EFW, FGM and STAFF) are used to investigate the
transient interaction between the solar wind and the Earth's
magnetic field. We study the crossing of an isolated FTE (January
26th, 2001, around 11:31 UT), presumably detached from the
magnetopause. As the FTE is crossed (i) the modulus of the ion
flow velocity (from CIS) is found to increase by about a factor
2, and its direction also changes. The ion flow is more or less
anti-parallel to the magnetic field, and parallel to the current
density (as determined from its magnetic signatures on the FGM
experiments aboard the 4-Cluster spacecraft), at the edges of the
FTE. Data from PEACE give evidence for enhanced electron fluxes,
in particular in the directions parallel and anti-parallel to B.
However the enhancement in the flux of relatively energetic
electrons (> 1 keV) lasts much longer than that of electrons
parallel to B, which suggests an escape from the magnetosphere.
Conversely, when field aligned electric currents are measured the
flux of medium energy electrons (about 100 eV) tends to be larger
for electrons flowing along the magnetic field, than for
electrons anti-parallel to B. This suggests that magnetosheath
electrons flow earthward, inside the FTE. Waves observed on STAFF
and EFW are shown to heat the electrons preferentially along the
magnetic field, thereby explaining why enhanced fluxes of
electrons, parallel and antiparallel to B are observed.
Torbert, R.B., Paschmann, G., Quinn, J., Baumjohaan, W., Mozer, F.S., Kistler, L., Mouikis, C., Puhl-Quinn, P., Andre, M., Kletzing, C.A. and Lindquist, P.- .
Three-Dimensional Electric Field Measurements at the Plasma Sheet Boundary as measured by the Electron Drift Instrument (EDI) and the Electric Field and Waves Instrument ( EFW ) on the CLUSTER Spacecraft
On CLUSTER, three dimensional electric
fields, including the component parallel to B, can be measured by
combining the information from the double-probe (EFW) , and those
of the Electron Drift Instrument (EDI). EFW measures the
potential difference between spherical probes spinning in a
plane, and computes the two components of the field in that spin
plane. EDI measures the drift-step vector, which is the
displacement of electron orbits after one gyro-period, and
computes the two components of the field in the plane
perpendicular to the magnetic field. Comparison of the field
along the axis which is common to these two planes, shows very
good agreement in many plasma regions. We will show data from the
night-time plasma sheet where large fields are sometimes observed
near the boundaries and particle populations make rapid changes.
These fields show a complex spatial and temporal structure that
appears to be neither constant in time nor space.
Wygant, J., Way, P., Keiling, A., Cattell, C.A., Lysak, R.L., Lysak, R.L., Mozer, F.S., Mende, S., Frey, A., Kletzing, C.A., Scudder, J.D., André, M. and Elphic, R.C.
Observations of Intense Electric and Magnetic Fields and Associated Poynting Flux Through-Out the Plasma Sheet During Major Geomagnetic Storms
We present observations from the EFI and MFE instruments on the Polar spacecraft obtained during several major geomagnetic storms (Dst < -100 nT)of intense electric field (> 40 mV/m, ptp) and magnetic field fluctuations (40-80 nT, ptp). . These spatially extensive field wave fields are observed at altitudes of 4-6 Re and last for 10-30 minutes in the spacecraft frame and can exist over a large fraction of the spatial extent of the plasma sheet. The fields map to a latitudinal extent on the ground of 4-6 degrees. This is a much larger spatial extent than the previously reported observations of intense Poynting flux due to Alfven wave at the outer boundary of the plasma sheet which were observed to last in the spacecraft frame a period of about 3 minutes and occurred during the expansion phase of substorms. The Poynting flux associated with the fields presented herein is directed along the magnetic field direction towards the Earth and exceeds 0.25 erg/cm^2 s. If mapped to 100 km altitude along converging magnetic field lines, the Poynting flux peak values can exceed 30 ergs/cm^2 s. This is sufficient to power some of the most intense aurora in the UVI data set. Preliminary analysis indicates that the ratio of E/B for these waves is consistent with a mixture of Alfvenic fluctuations interspersed with steady state electric fields closing in the ionosphere through field aligned currents. We will compare these observations of intense Poynting flux to simultaneously obtained images of the aurora obtained from Polar and IMAGE spacecraft Ultravioltet Imagers and the associated estimates of the electron energy flux . The data from the four Cluster spacecraft will be analyzed to provide estimates of the spatial scale sizes of the waves from similar kinds of events.
EGS XXVII General Assembly, Nice (2002)
André, M. et al
Multi-Spacecraft Observations of Thin Layers
at the Magnetopause (invited)
Backrud, M., André, M., Buchert, S., Olsson, A., Vaivads, A., Wahlund, J-E., Balogh, A., Cornilleau-Wehrlin, N., Fazakerley, A., Reme, H.
Cluster observations of broadband waves in the auroral zone
Behlke, R., André, M., Vaivads, A., Eriksson, A.I., Buchert, S., Lucek, E., Balogh, A., Bale, S., Mann, G., Schwartz, S.J.
Short Large Amplitude Magnetic Structures (SLAMS) are
observed in the upstream region of the quasi-parallel region of
the Earth´s bow shock
Morooka, M. et al
Dayside High Latitude Auroral Particle Acceleration
Observed by the Cluster Satellites
Stenberg, G. et al
Multi-satellite observations of the wavevector of whistler
waves near the magnetopause
Sundkvist, D., André, M., Cornilleau-Wehrlin, N., Dunlop, M., Vaivads, A., Wahlund, J-E.
Cluster II observations of broadband ELF emissions and
energy transport in the polar cusp
The simple-pole distribution function for a magnetized
Cluster Auroral Team, The auroral field-aligned
acceleration -Cluster results (invited)
URSI XXVII General Assembly, Maastricht, The Netherlands (2002)
André, M. et al
Multi-Spacecraft Observations of Thin Layers
at the Magnetopause (invited)
Gustafsson, V., André, M., Wahlund, L-E., Vaivads, A., Stasiewicz, K
Electric field measurements of low frequency waves on
AGU Fall Meeting, San Fransisco (2002)
André, M. et al
The Magnetopause at Ion and Electron Scales
Vaivads, A., André, M., Sundkvist, D, Wahlund, J-E., Buchert, S., Fazakerley, A., Savaud J. Cornilleau-Werlin, N.
Small Scale Magnetopause - Cluster Interferometric
IRF-days, Kiruna Sept 3, 2002
Cluster Observations of Broadband Extremely
Low Frequency Emissionbs and Energy Transport in the Cusp (oral
Astrobiology Conference, Graz, 16-18 Sept
Wahlund, J-E. et al
Possible Swedish Astrobiology Missions to
Cluster Workshop, RAL, UK, 2002/09/18-20
Cully, C.M., Donovan, E.F., Buchert, S. et al
Magnetic Reconnection Near Substorm Onset:
Multipoint In-situ Observations
Morooka, M. et al
On the Pulsation phenomena above the dayside auroral region