Space Weather: Observational
evidence for coupling and
feedbacks involving the ITM
Janet Kozyra
University of Michigan
http://growabrain.typepad.com/growabrain/2004/04/
rube_goldberg_m.html
16 June 2008
CEDAR Student Workshop
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The Sun & Earth form a complex system
which has characteristic properties
Prediction is difficult
based on knowledge of
components alone
Disney’s WALL-E (http://adisney.go.com/
disneyvideos/animatedfilms/wall-e/
“The whole is greater
than the sum of the
parts “
16 June 2008
CEDAR Student Workshop
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The Sun & Earth form a complex system
which has characteristic properties
Prediction is difficult
based on knowledge of
components alone
History matters
http://www.aps.org/publications/apsne
ws/200406/butterfly-effect.cfm
“Butterfly Effect”
16 June 2008
CEDAR Student Workshop
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The Sun & Earth form a complex system
which has characteristic properties
Prediction is difficult
based on knowledge of
components alone
History matters
Emergent features
Still from “The Mummy”
Mummy”, Universal Pictures, 2008
“Science of Surprise”
16 June 2008
CEDAR Student Workshop
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The Sun & Earth form a complex system
which has characteristic properties
Prediction is difficult
based on knowledge of
components alone
History matters
Emergent features
Negative and positive http://en.wikipedia.org/wiki/Rube_Goldberg_machine
feedbacks
“Simple cause & effect are rare.”
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CEDAR Student Workshop
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The Sun & Earth form a complex system
which has characteristic properties
Interactions between components define behavior
Not contained in the individual pieces
Break into smaller digestible pieces -- lose behavior
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CEDAR Student Workshop
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Close-Up on the Upper Atmosphere
Remember what we are dealing with …..
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Evidence for Active ITM Influences
throughout Geospace
Four coupling pathways:
Mass & momentum outflows
Solar wind energy inflow
Fundamental
physics:
Ion-neutral
coupling
Cross-scale
coupling
Active electrodynamic interactions
auroral
auroralparticles
particles
subsiding
subsiding
NO-rich
NO-rich
air
air
auroral
auroral
zone
zone
polar
polar
vortex
vortex
Isolation
Isolation
from
from
other
other
latitudes
latitudes
Reactive species: production
& transport
16 June 2008
Chemicaldynamical
coupling
CEDAR Student Workshop
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Evidence for Active ITM Influences
throughout Geospace
Four coupling pathways:
For this talk
concentrate on ….
Mass & momentum outflows
Solar wind energy inflow
Fundamental
physics:
Ion-neutral
coupling
Cross-scale
coupling
Active electrodynamic interactions
auroral
auroralparticles
particles
subsiding
subsiding
NO-rich
NO-rich
air
air
auroral
auroral
zone
zone
polar
polar
vortex
vortex
Isolation
Isolation
from
from
other
other
latitudes
latitudes
Reactive species: production
& transport
16 June 2008
Chemicaldynamical
coupling
CEDAR Student Workshop
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Mass and Momentum Outflow
Ionospheric Outflow: 2-Step Process
Outflow:
Acceleration
to > escape
velocity
Outflows
best
correlated
with solar
wind Pdyn
fluctuations:
Reason
Unknown
[c.f. Fok et
al., 2005]
Upwellling:
Increase in
scale height
Another “upwelling” process:
horizontal transport of enhanced Ne patches
After Strangeway et al., [2005] as summarized in Moore
and Horwitz, 2007 and Lotko, 2007
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CEDAR Student Workshop
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Mass and Momentum Outflow
SED
Dayside
TOI
12
800 km
18
Multiple
TOIs,
different
sources Ne
06
80
70
60
Accumulating evidence that
most of the mass, momentum,
and energy coupling occurs on
relatively small spatial scales.
Patch
being
created
Schunk, GEM tutorial, 2006
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CEDAR Student Workshop
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Mass and Momentum Outflow
patch
patch
patch
patch
Sondrestrom view
of polar cap patch
ions energized in
nightside auroral
zone.
Adapted
Adapted from
from
Semeter
Semeter et
et al.
al. 2003
2003
in
in Lotko
Lotko 2007
2007 review
review
H+
O+
HS
OS
Gardner
Gardner &
&
Schunk,
Schunk, 2005
2005
16 June 2008
Structured ion outflow
creates structured
neutral outflow through
charge exchange
CEDAR Student Workshop
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Mass and Momentum Outflow
Structured energy inputs
Solar wind (Poynting flux, Joule heating,
energy inflow
soft precipitation) and
convecting ionospheric
density structures
Effects plasma waves,
Cause structured
ring current & rad belt
“upwelling” of
composition, charge
ions, polar wind
exchange losses &
jets, neutral holes
Structured
atmospheric loss
Patchy plasma sheet
composition. Variable
oxygen geocorona
Lotko [2007], Sojka
and Schunk
references
16 June 2008
Neutral &
Ion
Outflows
Charge exchange & O
backsplash from H/H++
auroras creates
neutral O outflows
Further
acceleration by
waves and fieldaligned potentials
at high altitude
cause oxygen
outflows
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Oxygen ions dominate the magnetospheric plasma during
extreme events in the inner region. Patchy composition.
O+ more than 90%
of energy density
(at 6-8 RE) !!
O+ can
dominate even
for more
moderate solar
and magnetic
activity levels.
Variability due
to multiple
drivers.
[Greenspan &
(10/03)
(3/91)
(2/86)
Hamilton, JGR,
2002]
Nose et al., JGR, 2005
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CEDAR Student Workshop
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Ever-present <50 eV oxygen outflow
LENA sees at least 2 neutral
O populations under all
conditions:
Higher energy auroral O
Earth limbs
• A neutral hot O geocorona
• A higher energy upflowing O
population originating from
the auroral zone. Possibly
due to backsplash O from
H/H++ auroral precipitation
[Shematovich,
Shematovich, et
et al
al., 2006]
These upward O fluxes increase
in intensity with increasing
magnetic activity to a few x 1099
cm-2-2s-1-1.
16 June 2008
ram
Hot O geocorona
Wilson et al., 2003; 2005
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Suggested positive feedbacks on
magnetotail stability
Produces more
frequent and/or
more intense
auroral activity
Saturation of
the polar cap
potential
breaks positive
feedback loop.
Lotko, 2007
Increased
demand for
episodic
unloading of
tail flux
16 June 2008
Ionospheric outflow
from auroral activity
feeds O++ into
magnetotail
Magnetotail
stability
Mass loads
convection in
magnetosphere,
slows
reconnection rate
Less O++ in
dayside plasma
sheet implies
faster dayside
merging
Slower nightside
reconnection rate cannot
balance the dayside rate
CEDAR Student Workshop
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Evidence for the mass-loading of
reconnection flows
Consequences (review Moore & Horwitz, 2007): (1) reduces
Alfven speed of inflow to the dayside reconnection region,
(2) slows reconnection, (3) reduces convection
16 June 2008
Observed
occurrence
rate of cold
convecting
ions at the
dayside
magnetospher
e for northward
(left) and
southward
(right) IMF
[Chen and
Moore 2006].
CEDAR Student Workshop
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Evidence mass-loading by drainage
plume slows reconnection
Extension of
ionospheric
plasma into
the inner
magnetosphere
~10% effect for Ne < 10
cm-3 plumes. However,
Ne can reach 100 cm-3
Sign of weakened coupling to
the solar wind & evidence for
decreased reconnection rate.
Borovsky & Denton, 2006
Important component of mass circulation not included in MHD models
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CEDAR Student Workshop
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ITM Mass Loading of Magnetospheric
Convection
Solar Wind
Electric Field
Reduces
reconnection
rate, pc,
pc, &
outflows
Increases pc,
pc,
enhances
convection
Mass
Loading of
Convection
Massloading
slows
convection
Model result: Winglee
et al., 2002, as summarized by Lotko, 2007
16 June 2008
Greater
centrifugal
acceleration
of upflows
More
ionospheric
outflow
Higher O+
content of
plasmasheet
CEDAR Student Workshop
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ITM Mass Loading of Magnetospheric
Convection
As mass-loading increases in multi-fluid model, the convection potential drops toward
values predicted by AMIE model based on magnetometer data [Winglee et al., 2002]
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CEDAR Student Workshop
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Summary
• ITM is an active participant in Geospace system. Not
just a boundary condition.
• Growing evidence that mass & momentum flows and
electrodynamic parameters are all structured by the ITM.
• Coupling occurs on small spatial & temporal scales.
• Structured ion outflows produce structured neutral
outflows
• Coupling involves a broad range of scales, fluid &
kinetic processes & varies in complicated ways with
solar wind drivers
• Fundamental questions in the magnetosphere and
middle atmosphere cannot be answered without a more
complete knowledge of ITM processes
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CEDAR Student Workshop
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Highest priority ITM problems related to
Geospace system science
• Understand how fundamental ITM processes work so we
can recognize their signatures at the system level
• New ways of observing global patterns of energy inputs,
basic state parameters, and electrodynamic quantities.
Climatologies are not sufficient.
• Determine what spatial and temporal scales are needed
• Tackle the challenges & take the steps that will lead to a
revolution in our understanding of geospace as a tightly
coupled system of systems
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CEDAR Student Workshop
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Future Measurement Requirements
• Multi-point observations connecting solar
•
•
•
•
driving to auroral field-aligned transport
Connection between ionospheric (also
plasmaspheric) structures, transport & outflows.
Ion - neutral interactions
NOx in the polar night. Quantities related to
transport
ITM Complex System: Instantaneous global
patterns of energy inputs and electrodynamic
parameters.
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CEDAR Student Workshop
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